Restructure step 3: your server, Invite, version gate, AppGraph

- One server per app run (loopback, no password); Invite attaches an
  all-interfaces listener to the same server and Stop sharing detaches
  it (guests told with 4016); members, media and Up next never reset.
  No solo mode: you're home on your own server unless in a friend's.
- Navigation: none / yours / friend; a join passes a version gate on
  /health first (clear "they/you need to update", update offer).
- Invite as a value (host, port, name, password flag, version, fp
  reserved); addresses filtered (loopback, link-local, 198.18/15,
  bridges) and ranked; Sharing chip, Copy invite, Stop sharing.
- Alone looks like a plain player (alone replaces solo).
- AppGraph builds and disposes systems; widgets use AppScope;
  SessionState deleted; a test caps the remaining singletons.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/desktop/lib/main.dart

@@ -7,13 +7,13 @@ import 'package:media_kit/media_kit.dart';
 import 'package:sync_relay_core/core.dart';
 
 import 'app.dart';
+import 'src/app/app_graph.dart';
 import 'src/platform/app_log.dart';
-import 'src/platform/app_shutdown.dart';
+import 'src/platform/app_shutdown.dart' show closeAppWith;
 import 'src/platform/desktop/desktop_app_dirs.dart';
 import 'src/platform/desktop_entry.dart';
 import 'src/screens/home/ui.dart';
 import 'src/session/app_events.dart' show UpdateAvailable;
-import 'src/state/session_state.dart';
 import 'src/state/settings.dart';
 import 'src/update/update_controller.dart' show UpdateController, UpdatePhase, launchArgs;
 
@@ -46,20 +46,22 @@ Future<void> main(List<String> args) async {
   await startAppLogging(dirs);
   Hive.init(dirs.hive);
   await AppSettings.instance.ensureLoaded();
+  // The composition root: every system, made once.
+  final graph = AppGraph.build();
+  final ports = graph.ports;
   // Close button / Alt+F4: the orderly close ([shutDownApp]), so others
-  // see "left", a hosted server shuts down and no player outlives the
-  // engine.
-  final ports = SessionState.instance.ports;
+  // see "left", your server shuts down and no player outlives the engine.
+  final close = closeAppWith(graph);
   await ports.shell.start(
-      title: dirs.profile == null ? appName : '$appName [${dirs.profile}]', onCloseRequest: shutDownApp);
+      title: dirs.profile == null ? appName : '$appName [${dirs.profile}]', onCloseRequest: () => close());
   // Focus, minimise and restore feed auto sit-out and the Notifier (in
   // the background, notices go out as system notifications).
   ports.shell.watchActivity((a) {
-    SessionState.instance.coordinator.windowActivity(a);
-    SessionState.instance.notifier.window = a;
+    graph.coordinator.windowActivity(a);
+    graph.notifier.window = a;
   });
   try {
-    await SessionState.instance.loadForm();
+    await graph.forms.load();
   } catch (e, st) {
     debugPrint('load connect form failed: $e\n$st');
   }
@@ -74,10 +76,13 @@ Future<void> main(List<String> args) async {
     final s = updates.status.value;
     final version = s.manifest?.version;
     if (s.phase == UpdatePhase.available && version != null) {
-      SessionState.instance.notifier.notify(UpdateAvailable(version));
+      graph.notifier.notify(UpdateAvailable(version));
     }
   });
-  runApp(const WatchTogetherApp());
+  runApp(AppScope(graph: graph, child: const WatchTogetherApp()));
+  // Home: your own server, quietly (only this app can reach it until
+  // Invite).
+  unawaited(graph.navigation.start());
   // The sound device opens once the window is up, not on the first sound.
-  Future.delayed(const Duration(seconds: 2), SessionState.instance.sfx.warmUp);
+  Future.delayed(const Duration(seconds: 2), graph.sfx.warmUp);
 }

apps/desktop/lib/src/app/app_graph.dart

@@ -0,0 +1,156 @@
+import 'package:flutter/widgets.dart';
+
+import '../jellyfin/accounts.dart';
+import '../platform/app_log.dart' show appLogDir;
+import '../platform/desktop/desktop_ports.dart';
+import '../platform/ports/ports.dart';
+import '../screens/home/health_probe.dart';
+import '../session/connection.dart' show Connection;
+import '../session/identity.dart' show ClientIdentity, Profile;
+import '../session/navigation.dart';
+import '../session/notifier.dart';
+import '../session/session_coordinator.dart';
+import '../session/your_server.dart';
+import '../sfx/sfx.dart';
+import '../sfx/sound_bank.dart';
+import '../sfx/synth_sfx.dart';
+import '../state/connect_prefs.dart';
+import '../state/settings.dart';
+
+/// The composition root: builds the app's systems once (in `main`), wires
+/// them through their constructors and disposes them. No logic and no
+/// signals of its own. Widgets reach it through [AppScope].
+class AppGraph {
+  /// The platform (window, links, folders, yt-dlp, notifications).
+  final Ports ports;
+
+  /// Owns the app's audio device ([SynthSfx.dispose] on close).
+  final SynthSfx sfx;
+
+  /// Every toast, sound, system notification and activity-log line.
+  final Notifier notifier;
+
+  /// The link to whichever server this app is in.
+  final Connection connection;
+
+  final SessionCoordinator coordinator;
+
+  /// The connect form and recent servers.
+  final ConnectStore forms;
+
+  /// This app's own server, alive for the whole run.
+  final YourServer yourServer;
+
+  /// Home (your server) or a friend's.
+  final Navigation navigation;
+
+  AppGraph._({
+    required this.ports,
+    required this.sfx,
+    required this.notifier,
+    required this.connection,
+    required this.coordinator,
+    required this.forms,
+    required this.yourServer,
+    required this.navigation,
+  });
+
+  /// The desktop app's graph. Tests pass their own [ports], [identity]
+  /// (default: the install's stored one), [healthGet] and server starter.
+  factory AppGraph.build({
+    Ports? ports,
+    ClientIdentity? identity,
+    HealthGetter healthGet = defaultHealthGet,
+    ServerStarter? serverStarter,
+    JellyfinAccounts? jellyfin,
+  }) {
+    final p = ports ?? desktopPorts();
+    final sfx = SynthSfx(
+      volume: () => AppSettings.instance.soundVolume.peek(),
+      // A nudge is an explicit poke: it ignores its switch (not the volume).
+      enabled: (k) => k == SfxKind.nudge || !AppSettings.instance.soundsOff.peek().contains(k.name),
+      presetFor: soundPresetFor,
+    );
+    final notifier = Notifier(
+      sfx: sfx,
+      attention: p.shell.requestAttention,
+      system: p.notifications,
+      focusWindow: p.shell.focus,
+      prefs: () => AppSettings.instance.notifyPrefs,
+    );
+    final connection = Connection(notify: notifier.notify, identity: identity ?? ClientIdentity.stored());
+    final coordinator =
+        SessionCoordinator(notifier: notifier, connection: connection, ytDlp: p.links, jellyfin: jellyfin);
+    final forms = ConnectStore();
+    final yourServer = YourServer(
+      forms: forms,
+      jellyfin: jellyfin,
+      // The app's yt-dlp folder; '' (the server's own default) when the
+      // app-support folder is not available.
+      ytDlpDir: () async {
+        try {
+          return (await p.links.ytDlp).dir;
+        } catch (_) {
+          return '';
+        }
+      },
+      logDir: () => appLogDir,
+      starter: serverStarter,
+    );
+    final navigation = Navigation(
+      coordinator: coordinator,
+      yourServer: yourServer,
+      forms: forms,
+      healthGet: healthGet,
+    );
+    // The profile keeps its name in the connect form and pushes changes
+    // to whichever server this app is in.
+    Profile.instance
+      ..forms = forms
+      ..push = ({String? name, String? avatar}) {
+        if (navigation.online.peek()) coordinator.updateProfile(name: name, avatar: avatar);
+      };
+    return AppGraph._(
+      ports: p,
+      sfx: sfx,
+      notifier: notifier,
+      connection: connection,
+      coordinator: coordinator,
+      forms: forms,
+      yourServer: yourServer,
+      navigation: navigation,
+    );
+  }
+
+  Future<void> dispose() async {
+    navigation.dispose();
+    await coordinator.dispose();
+    await yourServer.stop();
+    await sfx.dispose();
+  }
+}
+
+/// The sound set [kind] plays from: its own pick in Settings, else the
+/// overall one.
+SoundPreset soundPresetFor(SfxKind kind) {
+  final s = AppSettings.instance;
+  final name = s.soundPresetFor.peek()[kind.name] ?? s.soundPreset.peek();
+  return SoundPreset.values.where((p) => p.name == name).firstOrNull ?? defaultPreset;
+}
+
+/// Hands the [AppGraph] to every widget below: `AppScope.of(context)`.
+/// The graph never changes, so reading it registers no dependency (safe
+/// in `initState`).
+class AppScope extends InheritedWidget {
+  final AppGraph graph;
+  const AppScope({super.key, required this.graph, required super.child});
+
+  static AppGraph of(BuildContext context) {
+    final scope = context.getInheritedWidgetOfExactType<AppScope>();
+    assert(scope != null, 'no AppScope above this widget');
+    return scope!.graph;
+  }
+
+  @override
+  bool updateShouldNotify(AppScope oldWidget) => !identical(graph, oldWidget.graph);
+}

apps/desktop/lib/src/controls/control_menus.dart

@@ -121,7 +121,7 @@ Future<void> runControlAction(BuildContext context, PlayerControlsModel model, C
       model.changeVideo();
     case ControlAction.copyLink:
       final link = model.link();
-      if (link != null) await copyToClipboard(link, done: 'Link copied');
+      if (link != null) await copyToClipboard(context, link, done: 'Link copied');
     case ControlAction.reload:
       model.reload();
     case ControlAction.markAllReady:

apps/desktop/lib/src/controls/model/controls_layout.dart

@@ -113,7 +113,7 @@ class ControlsSnapshot {
   final bool hasDuration;
 
   /// Watching alone (no one to mark ready).
-  final bool solo;
+  final bool alone;
 
   /// A link to copy (`SessionCoordinator.currentLink`).
   final bool hasLink;
@@ -126,7 +126,7 @@ class ControlsSnapshot {
     this.nextIsUpNext = false,
     this.hasChapters = false,
     this.hasDuration = false,
-    this.solo = false,
+    this.alone = false,
     this.hasLink = false,
     this.fullscreen = false,
     this.chatOpen = false,
@@ -167,7 +167,7 @@ List<ControlAction> menuActions(ControlsSnapshot s, Set<OptionalControl> hidden)
       ControlAction.skipForward => s.hasDuration,
       ControlAction.chat => hidden.contains(OptionalControl.chat),
       ControlAction.copyLink => s.hasLink,
-      ControlAction.markAllReady => !s.solo,
+      ControlAction.markAllReady => !s.alone,
       _ => true,
     })
       a,
@@ -208,7 +208,7 @@ String controlTooltip(BarControl c, ControlsSnapshot s) => switch (c) {
   BarControl.playPause => switch (s.play) {
     PlayState.playing => 'Pause for everyone (Space)',
     PlayState.waiting => 'Ready, waiting for the others (Space: not ready)',
-    PlayState.paused => s.solo ? 'Play (Space)' : 'Ready: play when everyone is (Space)',
+    PlayState.paused => s.alone ? 'Play (Space)' : 'Ready: play when everyone is (Space)',
     PlayState.finished => 'Ready (Space)',
   },
   BarControl.previous => 'Previous: ${s.previousLabel ?? ''}  (< or Shift+P)',

apps/desktop/lib/src/controls/model/controls_model.dart

@@ -7,7 +7,6 @@ import '../../playback/playback_controller.dart';
 import '../../queue/queue_controller.dart';
 import '../../session/session_coordinator.dart';
 import '../../shaders/shader_presets.dart';
-import '../../state/session_state.dart';
 import '../../state/settings.dart';
 import '../player_settings.dart' show applyShaderChoice;
 import '../volume.dart' as vol;
@@ -91,7 +90,7 @@ class PlayerControlsModel {
       nextIsUpNext: items.isNotEmpty,
       hasChapters: chapters.value.isNotEmpty,
       hasDuration: duration.value > Duration.zero,
-      solo: SessionState.instance.solo.value,
+      alone: coord.alone.value,
       // Not a signal: read again whenever the state changes.
       hasLink: coord.serverState.value != null && coord.currentLink() != null,
       fullscreen: fullscreen.value,
@@ -184,7 +183,7 @@ class PlayerControlsModel {
 
   /// Saved as the choice and applied live; a null quality keeps the
   /// saved one.
-  void pickShader(ShaderPreset preset, ShaderQuality? quality) => applyShaderChoice(preset, quality);
+  void pickShader(ShaderPreset preset, ShaderQuality? quality) => applyShaderChoice(coord, preset, quality);
 
   void toggleTimeDisplay() => settings.setTimeDisplay(settings.timeDisplay.peek().toggled);
 

apps/desktop/lib/src/controls/player_settings.dart

@@ -6,8 +6,9 @@ import 'package:sync_relay_core/core.dart' show JellyfinStreamType;
 
 import '../jellyfin/track_prefs.dart' show MpvTrack;
 import '../playback/playback_controller.dart' show PlaybackController, RenderMode;
+import '../session/session_coordinator.dart' show SessionCoordinator;
 import '../shaders/shader_presets.dart';
-import '../state/session_state.dart';
+import '../app/app_graph.dart';
 import '../shell/mark_problem.dart';
 import '../shell/motion.dart';
 import '../state/settings.dart';
@@ -200,11 +201,10 @@ class ProgressLineSetting extends StatelessWidget {
 
 /// Saves a shader choice (also used on the next join) and puts it on the
 /// running player, if any; the player announces the result.
-void applyShaderChoice(ShaderPreset preset, ShaderQuality? quality) {
+void applyShaderChoice(SessionCoordinator coord, ShaderPreset preset, ShaderQuality? quality) {
   final s = AppSettings.instance;
   if (quality != null) s.setShaderQuality(quality);
   s.setShaderPreset(preset);
-  final coord = SessionState.instance.coordinator;
   coord.markInput();
   coord.playback.applyShaders(announce: true);
 }
@@ -242,7 +242,7 @@ class ShaderPresetSetting extends StatelessWidget {
                 for (final p in ShaderPreset.values)
                   if (p != ShaderPreset.custom || hasCustom || preset == p) (p, p.label),
               ],
-              onChanged: (p) => applyShaderChoice(p, null),
+              onChanged: (p) => applyShaderChoice(AppScope.of(context).coordinator, p, null),
             ),
             if (preset.isAnime4k) ...[
               const SizedBox(width: 8),
@@ -250,7 +250,7 @@ class ShaderPresetSetting extends StatelessWidget {
                 key: const ValueKey('shader-quality'),
                 value: quality,
                 items: [for (final q in ShaderQuality.values) (q, q.label)],
-                onChanged: (q) => applyShaderChoice(preset, q),
+                onChanged: (q) => applyShaderChoice(AppScope.of(context).coordinator, preset, q),
               ),
             ],
           ],
@@ -265,9 +265,8 @@ class ShaderPresetSetting extends StatelessWidget {
 
 /// Puts the hwdec setting on the running player (mpv switches decoders
 /// on the fly). `SYNC_RELAY_HWDEC` wins, as at player start.
-Future<void> applyHwdecLive() async {
+Future<void> applyHwdecLive(PlaybackController playback) async {
   if ((Platform.environment['SYNC_RELAY_HWDEC'] ?? '').isNotEmpty) return;
-  final playback = SessionState.instance.coordinator.playback;
   if (!playback.alive.peek()) return;
   try {
     final dynamic platform = playback.player.platform;
@@ -308,7 +307,7 @@ class _HwdecSettingState extends State<HwdecSetting> {
           items: const [(HwdecMode.auto, 'Auto'), (HwdecMode.off, 'Off'), (HwdecMode.custom, 'Custom')],
           onChanged: (m) {
             _s.setHwdecMode(m);
-            applyHwdecLive();
+            applyHwdecLive(AppScope.of(context).coordinator.playback);
           },
         ),
         below: mode != HwdecMode.custom
@@ -324,7 +323,7 @@ class _HwdecSettingState extends State<HwdecSetting> {
                     border: OutlineInputBorder(),
                   ),
                   onChanged: _s.setHwdecCustom,
-                  onSubmitted: (_) => applyHwdecLive(),
+                  onSubmitted: (_) => applyHwdecLive(AppScope.of(context).coordinator.playback),
                 ),
               ),
       );
@@ -342,7 +341,7 @@ class TrackSetting extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final coord = SessionState.instance.coordinator;
+    final coord = AppScope.of(context).coordinator;
     return SignalBuilder(builder: (context) {
       final list = [
         for (final t in coord.playback.tracks.value)

apps/desktop/lib/src/files/ui/files_page.dart

@@ -6,7 +6,7 @@ import 'package:signals/signals_flutter.dart';
 
 import '../../shell/motion.dart';
 import '../../platform/ports/folder_access.dart';
-import '../../state/session_state.dart';
+import '../../app/app_graph.dart';
 import '../../widgets/app_menu.dart';
 import '../folder_store.dart';
 import '../name_parser.dart';
@@ -33,7 +33,6 @@ String? _lastOpen;
 final _expanded = <String>{};
 final _showRequests = ValueNotifier(0);
 
-FolderAccess get _folders => SessionState.instance.ports.folders;
 
 /// Opens [dir] (null: Recent) in the Files page: now if one is showing,
 /// else when it next opens.
@@ -52,8 +51,8 @@ void resetFilesPageSession() {
 }
 
 class FilesPage extends StatefulWidget {
-  /// Nobody else watches (offline or solo): no relay notice.
-  final bool solo;
+  /// Nobody else is in the server: no relay notice.
+  final bool alone;
   /// The file will stream from this computer through the server.
   final bool relayed;
   /// Plays [path] in the session; returns an error text, or null.
@@ -73,7 +72,7 @@ class FilesPage extends StatefulWidget {
 
   const FilesPage({
     super.key,
-    this.solo = false,
+    this.alone = false,
     required this.relayed,
     required this.onPlay,
     this.onAddToQueue,
@@ -112,6 +111,8 @@ class _Library {
 final _libraries = Expando<_Library>();
 
 class _FilesPageState extends State<FilesPage> {
+  FolderAccess get _folders => AppScope.of(context).ports.folders;
+
   late final ThumbCache _thumbs =
       widget.thumbnails == null ? ThumbCache.shared : ThumbCache(widget.thumbnails!);
   FolderStore get _store => widget.store ?? FolderStore.instance;
@@ -198,7 +199,7 @@ class _FilesPageState extends State<FilesPage> {
     if (path != null && mounted) await _play(path);
   }
 
-  static Future<String?> _pickVideo() async {
+  Future<String?> _pickVideo() async {
     final files = await _folders.pickFiles(dialogTitle: 'Pick a video', extensions: videoExtensions.toList());
     return files.firstOrNull;
   }
@@ -247,7 +248,7 @@ class _FilesPageState extends State<FilesPage> {
     final add = widget.onAddToQueue;
     if (add == null) return;
     final pick = await showAppMenu<int>(context, items: [
-      AppMenuItem(value: 0, label: widget.solo ? 'Play' : 'Put it up'),
+      AppMenuItem(value: 0, label: widget.alone ? 'Play' : 'Put it up'),
       const AppMenuItem(value: 1, label: 'Add to queue'),
       const AppMenuItem(value: 2, label: 'Play next'),
     ]);
@@ -375,7 +376,7 @@ class _FilesPageState extends State<FilesPage> {
     final top = <Widget>[
       _header(context, open),
       if (narrow) _chips(folders, open),
-      if (!widget.solo && widget.relayed) const _RelayNotice(),
+      if (!widget.alone && widget.relayed) const _RelayNotice(),
       AnimatedSize(
         duration: easeTime,
         curve: ease,
@@ -695,6 +696,8 @@ class _RecentRow extends StatefulWidget {
 }
 
 class _RecentRowState extends State<_RecentRow> {
+  FolderAccess get _folders => AppScope.of(context).ports.folders;
+
   FileStat? _stat;
 
   @override

apps/desktop/lib/src/jellyfin/browse_scope.dart

@@ -339,9 +339,9 @@ class BrowseScope extends InheritedWidget {
       case 2:
         queue!(item, next: true);
       case 3:
-        await copyToClipboard(jellyfinCopyTitle(item), done: 'Title copied');
+        if (context.mounted) await copyToClipboard(context, jellyfinCopyTitle(item), done: 'Title copied');
       case 4:
-        await openLink(jellyfinWebUrl(client.baseUrl, item.id, serverId: account.serverId));
+        if (context.mounted) await openLink(context, jellyfinWebUrl(client.baseUrl, item.id, serverId: account.serverId));
     }
   }
 

apps/desktop/lib/src/jellyfin/details_panel.dart

@@ -35,15 +35,15 @@ typedef _Data = ({
 
 /// The selected card's details, at the right of the library: banner,
 /// title, meta, "Put it up · S1E3" ("Play · S1E3" when watching
-/// [solo]), mark watched / unwatched, remove from Continue, overview and,
+/// [alone]), mark watched / unwatched, remove from Continue, overview and,
 /// for a series or an episode, the episode list (click picks which
 /// episode goes up, double-click puts it up). Reloads when the
 /// [controller]'s data version moves.
 class JellyfinDetailsPanel extends StatefulWidget {
   final BrowseController controller;
   final JellyfinSelection selection;
-  /// Nobody else watches (offline or solo): the button says Play.
-  final bool solo;
+  /// Nobody else is in the server: the button says Play.
+  final bool alone;
   /// Puts [item] (playable) up; returns an error text, or null when sent.
   final Future<String?> Function(JellyfinSelection item) onPutUp;
   /// Adds [item] to Up next (with next: right after what plays); null: no
@@ -57,7 +57,7 @@ class JellyfinDetailsPanel extends StatefulWidget {
     required this.onPutUp,
     this.onAddToQueue,
     required this.onClose,
-    this.solo = false,
+    this.alone = false,
   });
 
   @override
@@ -156,7 +156,7 @@ class _JellyfinDetailsPanelState extends State<JellyfinDetailsPanel> {
     final client = _client;
     final pick = await showAppMenu<int>(context, items: [
       if (queue) ...[
-        AppMenuItem(value: 0, label: widget.solo ? 'Play' : 'Put it up'),
+        AppMenuItem(value: 0, label: widget.alone ? 'Play' : 'Put it up'),
         const AppMenuItem(value: 1, label: 'Add to queue'),
         const AppMenuItem(value: 2, label: 'Play next'),
       ],
@@ -171,9 +171,9 @@ class _JellyfinDetailsPanelState extends State<JellyfinDetailsPanel> {
       case 2:
         await _queue(e, next: true);
       case 3:
-        await copyToClipboard(jellyfinCopyTitle(e), done: 'Title copied');
+        if (context.mounted) await copyToClipboard(context, jellyfinCopyTitle(e), done: 'Title copied');
       case 4:
-        await openLink(jellyfinWebUrl(client!.baseUrl, e.id, serverId: _serverId));
+        if (context.mounted) await openLink(context, jellyfinWebUrl(client!.baseUrl, e.id, serverId: _serverId));
     }
   }
 
@@ -308,7 +308,7 @@ class _JellyfinDetailsPanelState extends State<JellyfinDetailsPanel> {
       if (shown.communityRating != null) '★ ${shown.communityRating!.toStringAsFixed(1)}',
       if (!isSeries && shown.userData.played) 'Watched',
     ].join(' · ');
-    final verb = widget.solo ? 'Play' : 'Put it up';
+    final verb = widget.alone ? 'Play' : 'Put it up';
     final label = playable != null && isSeries ? '$verb · ${playable.episodeLabel ?? playable.name}' : verb;
     final inContinue = playable != null &&
         (playable.userData.isResumable || _c.continueKeys.contains(continueKey(playable)));
@@ -397,7 +397,7 @@ class _JellyfinDetailsPanelState extends State<JellyfinDetailsPanel> {
                     IconButton(
                       key: const ValueKey('details-open-jellyfin'),
                       tooltip: ReuseText.openInJellyfin,
-                      onPressed: () => openLink(jellyfinWebUrl(client.baseUrl, shown.id, serverId: _serverId)),
+                      onPressed: () => openLink(context, jellyfinWebUrl(client.baseUrl, shown.id, serverId: _serverId)),
                       icon: const Icon(Icons.open_in_browser_rounded),
                     ),
                 ],

apps/desktop/lib/src/platform/app_log.dart

@@ -6,7 +6,7 @@ import 'package:sync_relay_core/core.dart';
 
 import '../screens/home/ui.dart' show appName, displayVersion;
 import 'ports/app_dirs.dart';
-import '../state/session_state.dart';
+import '../app/app_graph.dart';
 
 // The app's log on disk (<app support>/logs/app-YYYY-MM-DD.log; core's
 // logging.dart writes, rotates and redacts it), debugPrint routed into it,
@@ -50,19 +50,19 @@ Future<void> startAppLogging(AppDirs dirs) async {
 /// the app log (its hosted server's records included), already redacted;
 /// with [sessionLog], the server's session log of the same hours after it
 /// (every member's shared lines and the server's, merged).
-Future<String> diagnosticsText({Duration since = const Duration(hours: 6), bool sessionLog = false}) async {
+Future<String> diagnosticsText(AppGraph graph, {Duration since = const Duration(hours: 6), bool sessionLog = false}) async {
   final b = StringBuffer()
     ..writeln('$appName ${displayVersion()}')
     ..writeln('OS: ${Platform.operatingSystem} ${Platform.operatingSystemVersion}')
     ..writeln('Dart: ${Platform.version.split(' ').first}');
   try {
-    final mpv = await SessionState.instance.coordinator.playback.mpvVersion().timeout(const Duration(seconds: 2));
+    final mpv = await graph.coordinator.playback.mpvVersion().timeout(const Duration(seconds: 2));
     b.writeln('mpv: ${mpv ?? 'no player yet'}');
   } catch (_) {
     b.writeln('mpv: unknown');
   }
   try {
-    final y = await SessionState.instance.ports.links.ytDlp.timeout(const Duration(seconds: 2));
+    final y = await graph.ports.links.ytDlp.timeout(const Duration(seconds: 2));
     final cookies = y.cookies.read(count: false);
     b.writeln('yt-dlp: ${y.version ?? 'not ready'}${y.lastError == null ? '' : ' (${y.lastError})'}, '
         'cookies: ${cookies == null ? 'none' : 'set'}');
@@ -74,7 +74,7 @@ Future<String> diagnosticsText({Duration since = const Duration(hours: 6), bool
   b.writeln('--- last ${since.inHours} h of the log ---');
   b.write(files?.recent(since) ?? '');
   if (sessionLog) {
-    final server = await SessionState.instance.coordinator.sessionLog(hours: since.inHours);
+    final server = await graph.coordinator.sessionLog(hours: since.inHours);
     b
       ..writeln()
       ..writeln("--- last ${since.inHours} h of the server's session log ---")

apps/desktop/lib/src/platform/app_shutdown.dart

@@ -4,7 +4,7 @@ import 'dart:io';
 import 'package:flutter/foundation.dart';
 
 import '../files/thumbnails.dart';
-import '../state/session_state.dart';
+import '../app/app_graph.dart';
 
 // The one way out of the app (close button, Alt+F4, Update and restart).
 // Order matters: every mpv player goes before the engine does (a live one
@@ -18,33 +18,43 @@ bool _shuttingDown = false;
 /// True once [shutDownApp] started.
 bool get shuttingDown => _shuttingDown;
 
+/// The systems the close stops; `main` hands them over once.
+AppGraph? _graph;
+
+/// Makes [graph] the one [shutDownApp] stops and returns the close
+/// request handler for the window.
+Future<void> Function() closeAppWith(AppGraph graph) {
+  _graph = graph;
+  return shutDownApp;
+}
+
 /// Hides the window, releases every player and the sound device, leaves
-/// (the `bye` goes out first, so others see "left" at once; a hosted
+/// (the `bye` goes out first, so others see "left" at once; then your
 /// server stops), runs [beforeQuit], then closes the window. [restart]
 /// (Update and restart) leaves without the `bye`: the member stays
 /// `gone`, and the restarted app, same client id, takes it back within
 /// the grace. Every step is bounded; a second call does nothing.
 Future<void> shutDownApp({Future<void> Function()? beforeQuit, bool restart = false}) async {
-  if (_shuttingDown) return;
+  final graph = _graph;
+  if (_shuttingDown || graph == null) return;
   _shuttingDown = true;
-  final session = SessionState.instance;
-  final shell = session.ports.shell;
+  final shell = graph.ports.shell;
   final total = Stopwatch()..start();
   await _step('window save', shell.saveWindow(), const Duration(milliseconds: 500));
   await _step('hide', shell.hide(), const Duration(milliseconds: 500));
   await Future.wait([
-    _step('players', session.coordinator.releasePlayers(), const Duration(seconds: 3)),
+    _step('players', graph.coordinator.releasePlayers(), const Duration(seconds: 3)),
     _step('thumbnails', cancelAllThumbnails(), const Duration(milliseconds: 1500)),
-    _step('sounds', session.sfx.dispose(), const Duration(milliseconds: 500)),
+    _step('sounds', graph.sfx.dispose(), const Duration(milliseconds: 500)),
   ]);
   // Windows: media_kit_video frees a player's video output on a thread of
   // its own after dispose returns; it must be done before the engine
   // stops, or the plugin's teardown waits on it for good.
   if (Platform.isWindows) await Future.delayed(const Duration(milliseconds: 300));
-  // Jellyfin stop report, last diagnostics, the bye (flushed), then the
-  // hosted server: 3 s in all.
-  await _step('leave', session.leave(bye: !restart), const Duration(milliseconds: 2500));
-  await _step('server stop', session.stopServer(), const Duration(milliseconds: 500));
+  // Jellyfin stop report, last diagnostics, the bye (flushed), then your
+  // server: 3 s in all.
+  await _step('leave', graph.navigation.leave(bye: !restart), const Duration(milliseconds: 2500));
+  await _step('server stop', graph.yourServer.stop(), const Duration(milliseconds: 500));
   if (beforeQuit != null) await _step('before quit', beforeQuit(), const Duration(seconds: 3));
   debugPrint('close: ready to quit after ${total.elapsedMilliseconds} ms');
   await shell.quit();

apps/desktop/lib/src/platform/ports/ports.dart

@@ -12,7 +12,7 @@ export 'system_notifications.dart';
 export 'url_opener.dart';
 
 /// The platform as the app sees it: one set, made in the composition
-/// root ([SessionState]) and handed on from there.
+/// root ([AppGraph]) and handed on from there.
 class Ports {
   final ShellPort shell;
   final UrlOpener urls;

apps/desktop/lib/src/queue/queue_controller.dart

@@ -181,7 +181,7 @@ class QueueController {
         );
       case LinkMedia(:final url, :final anyway):
         // Alone, a link plays direct: there is nobody to pass it on to.
-        final relay = coord.solo ? LinkRelay.direct : pick.relay;
+        final relay = coord.alone.peek() ? LinkRelay.direct : pick.relay;
         final linked = await mediaForLink(coord.jellyfin, url);
         final ref = linked.jellyfin;
         if (ref != null) {

apps/desktop/lib/src/queue/queue_ui.dart

@@ -18,7 +18,7 @@ import '../shell/avatar.dart';
 import '../shell/handoff.dart' show handoffHolds;
 import '../shell/library_link.dart' show LinkPreview, cachedLinkPreview;
 import '../shell/motion.dart';
-import '../state/session_state.dart';
+import '../app/app_graph.dart';
 import '../widgets/app_menu.dart' show AppGlass, AppMenuItem, AppMenuStyle, showAppMenu;
 import '../widgets/copy_open.dart';
 import '../widgets/text_focus.dart' show KeyboardClaim;
@@ -641,7 +641,7 @@ class _QueuePanelState extends State<QueuePanel> {
 
   /// Ctrl+V: the clipboard's video files, else the links in its text.
   Future<void> _paste() async {
-    final clip = await (widget.readClipboard ?? SessionState.instance.ports.shell.readPaste)();
+    final clip = await (widget.readClipboard ?? AppScope.of(context).ports.shell.readPaste)();
     final picks = _picksFrom([...clip.files, ...?clip.text?.split(RegExp(r'\s+'))]);
     if (!mounted) return;
     if (picks.isEmpty) {
@@ -682,7 +682,8 @@ class _QueuePanelState extends State<QueuePanel> {
       final row = rows[i];
       if (p case LinkMedia(:final url)) {
         // Its title and picture while it resolves (at once when seen before).
-        unawaited((widget.preview ?? cachedLinkPreview)(url).then((v) {
+        final probe = AppScope.of(context).ports.links.probe;
+        unawaited((widget.preview ?? (u) => cachedLinkPreview(u, probe: probe))(url).then((v) {
           if (mounted) setState(() => row.preview = v);
         }, onError: (Object _) {}));
       }
@@ -768,13 +769,13 @@ class _QueuePanelState extends State<QueuePanel> {
       case 'remove':
         _q.remove(item.id);
       case 'title':
-        await copyToClipboard(item.title, done: 'Title copied');
+        if (context.mounted) await copyToClipboard(context, item.title, done: 'Title copied');
       case 'link':
-        await copyToClipboard(link!, done: 'Link copied');
+        if (context.mounted) await copyToClipboard(context, link!, done: 'Link copied');
       case 'open':
-        await openLink(link!);
+        if (context.mounted) await openLink(context, link!);
       case 'jellyfin':
-        await openLink(page!);
+        if (context.mounted) await openLink(context, page!);
     }
   }
 
@@ -814,7 +815,7 @@ class _QueuePanelState extends State<QueuePanel> {
   @override
   Widget build(BuildContext context) {
     final height = MediaQuery.sizeOf(context).height;
-    final drop = SessionState.instance.ports.shell.dropTarget(
+    final drop = AppScope.of(context).ports.shell.dropTarget(
       onEnter: () => setState(() => _dragging = true),
       onExit: () => setState(() => _dragging = false),
       onDrop: (paths, _) {
@@ -1192,8 +1193,8 @@ IconData howIcon(QueueHow how) => switch (how) {
     };
 
 /// Who added it: their picture (still here) or initial, and name.
-AvatarInfo _adderAvatar(QueueItem item, List<MemberView> members) {
-  final coord = SessionState.instance.coordinator;
+AvatarInfo _adderAvatar(BuildContext context, QueueItem item, List<MemberView> members) {
+  final coord = AppScope.of(context).coordinator;
   for (final m in members) {
     if (m.id == item.by) return memberAvatarInfo(m, coord.serverState.peek(), coord);
   }
@@ -1227,7 +1228,7 @@ class _MetaLine extends StatelessWidget {
         children: [
           if (dur.isNotEmpty) ...[Text(dur, style: style), dot],
           Text('added by ', style: style),
-          StatusAvatar(info: _adderAvatar(item, members), size: fontSize + 3, badges: false, ring: false),
+          StatusAvatar(info: _adderAvatar(context, item, members), size: fontSize + 3, badges: false, ring: false),
           const SizedBox(width: 4),
           Text(name, style: style),
           dot,
@@ -1243,7 +1244,7 @@ class _MetaLine extends StatelessWidget {
       children: [
         if (dur.isNotEmpty) ...[Text(dur, style: style), dot],
         Text('added by ', style: style),
-        StatusAvatar(info: _adderAvatar(item, members), size: fontSize + 3, badges: false, ring: false),
+        StatusAvatar(info: _adderAvatar(context, item, members), size: fontSize + 3, badges: false, ring: false),
         const SizedBox(width: 4),
         // Capped rather than flexible: two flexibles split the room in
         // half and would cut the end off even when it fits.

apps/desktop/lib/src/schedule/ui/schedule_card.dart

@@ -13,7 +13,7 @@ enum CardAction {
   none,
   putUp,
 
-  /// Available, nobody else watching (offline or solo): plays it here.
+  /// Available, nobody else in the server: plays it here.
   play,
   request,
   requestSeries,

apps/desktop/lib/src/schedule/ui/schedule_page.dart

@@ -24,9 +24,8 @@ import 'schedule_card.dart';
 enum ScheduleFilter { jellyfin, all }
 
 class SchedulePage extends StatefulWidget {
-  /// Nobody else watches (offline or solo): available episodes say Play
-  /// (offline that starts a solo session).
-  final bool solo;
+  /// Nobody else is in the server (D9): available episodes say Play.
+  final bool alone;
 
   /// Puts a Jellyfin episode up in the server; returns an error to show.
   final Future<String?> Function(JellyfinMedia pick) onPutUp;
@@ -43,7 +42,7 @@ class SchedulePage extends StatefulWidget {
 
   const SchedulePage({
     super.key,
-    this.solo = false,
+    this.alone = false,
     required this.onPutUp,
     this.onAddToQueue,
     required this.onToast,
@@ -228,7 +227,7 @@ class _SchedulePageState extends State<SchedulePage> {
 
   (CardAction, String?) _actionFor(ScheduleEntry e) {
     if (e.status == ScheduleStatus.available || e.status == ScheduleStatus.inLibrary) {
-      final put = widget.solo ? CardAction.play : CardAction.putUp;
+      final put = widget.alone ? CardAction.play : CardAction.putUp;
       if (e.jellyfinSeriesId == null) return (put, 'Not linked to a Jellyfin series yet');
       return (put, null);
     }
@@ -287,7 +286,7 @@ class _SchedulePageState extends State<SchedulePage> {
     final add = widget.onAddToQueue;
     if (add == null) return;
     final pick = await showAppMenu<int>(context, items: [
-      AppMenuItem(value: 0, label: widget.solo ? 'Play' : 'Put it up'),
+      AppMenuItem(value: 0, label: widget.alone ? 'Play' : 'Put it up'),
       const AppMenuItem(value: 1, label: 'Add to queue'),
       const AppMenuItem(value: 2, label: 'Play next'),
     ]);

apps/desktop/lib/src/screens/home/about_page.dart

@@ -3,7 +3,7 @@ import 'package:signals/signals_flutter.dart';
 
 import '../../platform/app_log.dart';
 import '../../shell/mark_problem.dart';
-import '../../state/session_state.dart';
+import '../../app/app_graph.dart';
 import '../../state/settings.dart';
 import '../../update/update_controller.dart';
 import '../../widgets/app_menu.dart';
@@ -43,10 +43,10 @@ class AboutPanel extends StatelessWidget {
                   IconButton(
                     tooltip: ReuseText.copyLink,
                     icon: const Icon(Icons.copy, size: 18),
-                    onPressed: () => copyToClipboard(repoUrl, done: 'Link copied'),
+                    onPressed: () => copyToClipboard(context, repoUrl, done: 'Link copied'),
                   ),
                   FilledButton.tonalIcon(
-                    onPressed: () => openLink(repoUrl),
+                    onPressed: () => openLink(context, repoUrl),
                     icon: const Icon(Icons.open_in_new, size: 18),
                     label: const Text('Source'),
                   ),
@@ -75,7 +75,7 @@ class AboutPanel extends StatelessWidget {
                   ),
                   const MarkProblemButton(outlined: true),
                   OutlinedButton.icon(
-                    onPressed: appLogDir == null ? null : () => _openLogs(),
+                    onPressed: appLogDir == null ? null : () => _openLogs(context),
                     icon: const Icon(Icons.folder_open, size: 18),
                     label: const Text('Open logs folder'),
                   ),
@@ -102,7 +102,8 @@ class AboutPanel extends StatelessWidget {
   /// In a session it asks whether to add the server's session log.
   static Future<void> _copyDiagnostics(BuildContext context) async {
     var withServer = false;
-    if (SessionState.instance.route.peek() == AppRoute.session) {
+    final graph = AppScope.of(context);
+    if (graph.navigation.online.peek()) {
       final pick = await showAppMenu<bool>(context, items: const [
         AppMenuItem(value: false, label: "This app's log"),
         AppMenuItem(value: true, label: "This app's and the server's session log"),
@@ -110,17 +111,20 @@ class AboutPanel extends StatelessWidget {
       if (pick == null) return;
       withServer = pick;
     }
-    final text = await diagnosticsText(sessionLog: withServer);
+    final text = await diagnosticsText(graph, sessionLog: withServer);
     final saved = await saveDiagnostics(text);
-    await copyToClipboard(text,
+    if (!context.mounted) return;
+    await copyToClipboard(context, text,
         done: saved == null ? 'Diagnostics copied' : 'Diagnostics copied (also saved in the logs folder)');
   }
 
-  static Future<void> _openLogs() async {
+  static Future<void> _openLogs(BuildContext context) async {
     final dir = appLogDir;
     if (dir == null) return;
-    if (!await SessionState.instance.ports.folders.reveal(dir)) {
-      await copyToClipboard(dir, done: "Couldn't open it — folder path copied");
+    final folders = AppScope.of(context).ports.folders;
+    if (!await folders.reveal(dir)) {
+      if (!context.mounted) return;
+      await copyToClipboard(context, dir, done: "Couldn't open it — folder path copied");
     }
   }
 }

apps/desktop/lib/src/screens/home/connect_flow.dart

@@ -2,26 +2,35 @@ import 'package:flutter/foundation.dart';
 
 import '../../session/connection.dart' show connectErrorText;
 import '../../session/identity.dart';
+import '../../session/navigation.dart';
 import '../../session/session_coordinator.dart';
-import '../../state/session_state.dart';
+import '../../state/connect_prefs.dart';
 import '../../sync/sync_client.dart' show HelloRefused;
+import 'health_probe.dart' show VersionGateRefused;
 
-/// What a card shows under its fields after a failed attempt.
+/// What the Join card shows under its fields after a failed attempt.
+/// [offerUpdate]: this app is the older one (the version gate), so the
+/// card offers the updater.
 class CardError {
   final String title;
   final String message;
-  const CardError(this.title, this.message);
+  final bool offerUpdate;
+  const CardError(this.title, this.message, {this.offerUpdate = false});
 }
 
-/// Host/Join submit state for the strip's two connect cards. One attempt at a time;
-/// [cancel] abandons it via [SessionState.cancelPending].
+/// The Join card's submit state, owned by the shell so an attempt and its
+/// error outlive the card. One attempt at a time; [cancel] abandons it
+/// ([Navigation.cancelPending]).
 class ConnectFlow extends ChangeNotifier {
-  ConnectFlow({SessionState? session}) : _session = session ?? SessionState.instance;
-  final SessionState _session;
+  ConnectFlow({required this.navigation, required this.forms, this.profile});
+  final Navigation navigation;
+  final ConnectStore forms;
+  /// Name and picture for the hello (default: the app's).
+  final Profile? profile;
 
-  ConnectMode? busy;
-  final errors = <ConnectMode, CardError?>{};
-  final notices = <ConnectMode, String?>{};
+  bool busy = false;
+  CardError? error;
+  String? notice;
   int _attempt = 0;
   bool _disposed = false;
 
@@ -35,116 +44,101 @@ class ConnectFlow extends ChangeNotifier {
     if (!_disposed) notifyListeners();
   }
 
-  void showError(ConnectMode mode, CardError error) {
-    errors[mode] = error;
-    notices[mode] = null;
+  void showError(CardError e) {
+    error = e;
+    notice = null;
     _notify();
   }
 
-  void clearError(ConnectMode mode) {
-    if (errors[mode] == null && notices[mode] == null) return;
-    errors[mode] = null;
-    notices[mode] = null;
+  void clearError() {
+    if (error == null && notice == null) return;
+    error = null;
+    notice = null;
     _notify();
   }
 
   /// Validates and builds the params; throws [FormatException] with a
   /// user-facing message. [avatar] is the base64 picture (the profile's).
-  /// Hosting puts nothing up: what to watch is picked in the library.
-  static ConnectParams buildParams(ConnectMode mode, ConnectForm f, {String avatar = ''}) {
-    final rawPort = mode == ConnectMode.host ? f.hostPort : f.port;
-    final port = int.tryParse(rawPort.trim());
+  static ConnectParams buildParams(ConnectForm f, {String avatar = ''}) {
+    final port = int.tryParse(f.port.trim());
     if (port == null || port <= 0 || port > 65535) {
       throw const FormatException('port must be 1–65535');
     }
     if (f.name.trim().isEmpty) {
       throw const FormatException('set your display name first (click your avatar at the top left)');
     }
-    if (mode == ConnectMode.join && f.host.trim().isEmpty) {
+    if (f.host.trim().isEmpty) {
       throw const FormatException('enter the server address');
     }
-    return ConnectParams(
-      host: f.host.trim(),
-      port: port,
-      secret: mode == ConnectMode.host ? f.hostSecret : f.secret,
-      name: f.name.trim(),
-      avatar: avatar,
-    );
+    return ConnectParams(host: f.host.trim(), port: port, secret: f.secret, name: f.name.trim(), avatar: avatar);
   }
 
-  /// [edit] fills the card's fields into a copy of the last form, so the
-  /// other card's saved values survive.
-  Future<void> submit(ConnectMode mode, void Function(ConnectForm f) edit) async {
-    if (busy != null) return;
+  /// [edit] fills the card's fields into a copy of the form; the form is
+  /// saved whatever happens (a failed join is when the user wants it back).
+  Future<void> submit(void Function(ConnectForm f) edit) async {
+    if (busy) return;
     final myAttempt = ++_attempt;
-    final form = _session.lastForm.copy();
+    final form = forms.form.copy();
     edit(form);
     form.name = form.name.trim();
     form.host = form.host.trim();
-    busy = mode;
-    errors[mode] = null;
-    notices[mode] = null;
+    busy = true;
+    error = null;
+    notice = null;
     _notify();
 
     ConnectParams params;
     try {
-      final profile = Profile.instance;
+      final profile = this.profile ?? Profile.instance;
       await profile.ensureLoaded();
-      params = buildParams(mode, form, avatar: profile.avatarBase64());
+      params = buildParams(form, avatar: profile.avatarBase64());
     } catch (e) {
       if (myAttempt != _attempt) return;
-      busy = null;
-      errors[mode] = CardError('Check the form',
-          e is FormatException ? e.message : 'check the form and try again');
+      busy = false;
+      error = CardError('Check the form', e is FormatException ? e.message : 'check the form and try again');
       _notify();
       return;
     }
-    final fromSolo = mode == ConnectMode.host && _session.solo.value;
+    forms.form
+      ..host = form.host
+      ..port = form.port
+      ..secret = form.secret;
     try {
-      if (mode == ConnectMode.host) {
-        await _session.host(params, form);
-      } else {
-        await _session.join(params, form);
-      }
+      await navigation.join(params);
     } catch (e) {
       if (myAttempt != _attempt) return;
-      busy = null;
-      // A refusal says why in plain words (an older host, a wrong password,
-      // another window).
-      errors[mode] = CardError('Could not connect', e is HelloRefused ? connectErrorText(e) : '$e');
+      busy = false;
+      // In plain words: the version gate (who has to update), a refusal
+      // (an older host, a wrong password, another window), offline.
+      error = switch (e) {
+        VersionGateRefused(:final message, :final youUpdate) =>
+          CardError("Versions don't match", message, offerUpdate: youUpdate),
+        HelloRefused() => CardError('Could not connect', connectErrorText(e)),
+        _ => CardError('Could not connect', '$e'),
+      };
       _notify();
+      await forms.saveQuietly();
       return;
     }
     if (myAttempt != _attempt) {
-      // Cancelled after it got through: back out (an Invite: back to solo).
+      // Cancelled after it got through: back home.
       try {
-        if (fromSolo) {
-          await _session.cancelInvite();
-        } else {
-          await _session.leave();
-          await _session.stopServer();
-        }
+        await navigation.goHome();
       } catch (_) {}
       return;
     }
-    busy = null;
+    busy = false;
     _notify();
-    await _session.rememberServer(RecentServer(
-      hosted: mode == ConnectMode.host,
-      host: mode == ConnectMode.host ? '' : form.host,
-      port: mode == ConnectMode.host ? form.hostPort.trim() : form.port.trim(),
-      secret: mode == ConnectMode.host ? form.hostSecret : form.secret,
-    ));
   }
 
   Future<void> cancel() async {
-    final mode = busy;
+    final was = busy;
     _attempt++;
     try {
-      await _session.cancelPending();
+      await navigation.cancelPending();
     } catch (_) {}
-    busy = null;
-    if (mode != null) notices[mode] = 'Cancelled';
+    busy = false;
+    if (was) notice = 'Cancelled';
     _notify();
   }
 }

apps/desktop/lib/src/screens/home/connect_status.dart

@@ -1,21 +1,20 @@
 import 'package:flutter/material.dart';
 
-import '../../state/session_state.dart';
+import '../../update/update_controller.dart';
 import 'connect_flow.dart';
 import 'ui.dart';
+import 'update_indicator.dart' show runUpdateCheck;
 
-/// The submit button for one [ConnectMode], swapped for a progress bar and
-/// Cancel while that attempt runs. Disabled while the other mode is busy.
+/// The Join button, swapped for a progress bar and Cancel while the
+/// attempt runs.
 class ConnectButton extends StatelessWidget {
   final ConnectFlow flow;
-  final ConnectMode mode;
   final String label;
   final VoidCallback onSubmit;
   final bool expand;
   const ConnectButton({
     super.key,
     required this.flow,
-    required this.mode,
     required this.label,
     required this.onSubmit,
     this.expand = false,
@@ -23,8 +22,7 @@ class ConnectButton extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final busyHere = flow.busy == mode;
-    if (busyHere) {
+    if (flow.busy) {
       return SizedBox(
         width: expand ? null : 220,
         child: Column(
@@ -35,10 +33,7 @@ class ConnectButton extends StatelessWidget {
             const SizedBox(height: 4),
             Row(
               children: [
-                Expanded(
-                  child: Text(mode == ConnectMode.host ? 'Starting server…' : 'Connecting…',
-                      style: Theme.of(context).textTheme.bodySmall),
-                ),
+                Expanded(child: Text('Connecting…', style: Theme.of(context).textTheme.bodySmall)),
                 TextButton(onPressed: flow.cancel, child: const Text('Cancel')),
               ],
             ),
@@ -46,35 +41,48 @@ class ConnectButton extends StatelessWidget {
         ),
       );
     }
-    final button = FilledButton(
-      onPressed: flow.busy != null ? null : onSubmit,
-      child: Text(label),
-    );
+    final button = FilledButton(onPressed: onSubmit, child: Text(label));
     return expand ? SizedBox(width: double.infinity, child: button) : button;
   }
 }
 
-/// Last error or notice for [mode], or nothing.
+/// The last error or notice, or nothing. A version gate that says this
+/// app is the older one offers the update ([updates], default the app's
+/// [UpdateController]).
 class ConnectFeedback extends StatelessWidget {
   final ConnectFlow flow;
-  final ConnectMode mode;
-  const ConnectFeedback({super.key, required this.flow, required this.mode});
+  final UpdateController? updates;
+  const ConnectFeedback({super.key, required this.flow, this.updates});
 
   @override
   Widget build(BuildContext context) {
-    final error = flow.errors[mode];
-    final notice = flow.notices[mode];
+    final error = flow.error;
+    final notice = flow.notice;
     if (error != null) {
       return Padding(
         padding: const EdgeInsets.only(top: 12),
-        child: ErrorBox(title: error.title, message: error.message),
+        child: Column(
+          crossAxisAlignment: CrossAxisAlignment.stretch,
+          children: [
+            ErrorBox(title: error.title, message: error.message),
+            if (error.offerUpdate)
+              Align(
+                alignment: Alignment.centerLeft,
+                child: TextButton.icon(
+                  key: const ValueKey('join-update'),
+                  onPressed: () => runUpdateCheck(updates, true),
+                  icon: const Icon(Icons.system_update_alt, size: 16),
+                  label: const Text('Check for the update'),
+                ),
+              ),
+          ],
+        ),
       );
     }
     if (notice != null) {
       return Padding(
         padding: const EdgeInsets.only(top: 12),
-        child: Text(notice,
-            style: Theme.of(context).textTheme.bodySmall?.copyWith(color: Colors.grey)),
+        child: Text(notice, style: Theme.of(context).textTheme.bodySmall?.copyWith(color: Colors.grey)),
       );
     }
     return const SizedBox.shrink();

apps/desktop/lib/src/screens/home/health_probe.dart

@@ -10,26 +10,61 @@ typedef HealthGetter = Future<String> Function(Uri uri);
 const healthPollEvery = Duration(seconds: 10);
 const _timeout = Duration(seconds: 4);
 
-/// What a recent-server tile shows: unknown until the first probe answers.
+/// Whether this app and a server have a wire version in common.
+enum VersionFit {
+  /// Their ranges meet: the join can go ahead.
+  ok,
+  /// The server's newest version is older than anything this app speaks.
+  theyUpdate,
+  /// The server's oldest version is newer than anything this app speaks.
+  youUpdate,
+}
+
+/// [VersionFit] of a server that speaks [min] .. [max] (`/health`
+/// `protoMin` / `protoMax`), against this build's
+/// [RelayConstants.protoMin] .. [RelayConstants.protoMax].
+VersionFit versionFit(int min, int max,
+    {int ownMin = RelayConstants.protoMin, int ownMax = RelayConstants.protoMax}) {
+  if (max < ownMin) return VersionFit.theyUpdate;
+  if (min > ownMax) return VersionFit.youUpdate;
+  return VersionFit.ok;
+}
+
+/// What a recent-server row and the version gate read from `/health`:
+/// unknown until the first probe answers.
 class ServerHealth {
   final bool online;
   final String name;
-  final int? proto;
+  /// The server's wire range (`protoMin` .. `protoMax`; a server too old
+  /// to say has only `proto`, used for both). Null when it says nothing.
+  final int? protoMin;
+  final int? protoMax;
   final int viewers;
   /// Its Starsync version (`version`), '' from a server too old to say.
   final String version;
   const ServerHealth.offline()
       : online = false,
         name = '',
-        proto = null,
+        protoMin = null,
+        protoMax = null,
         viewers = 0,
         version = '';
-  const ServerHealth.online({required this.name, this.proto, this.viewers = 0, this.version = ''})
+  const ServerHealth.online({required this.name, this.protoMin, this.protoMax, this.viewers = 0, this.version = ''})
       : online = true;
 
-  /// True when the server speaks another protocol than this build.
-  bool get needsUpdate =>
-      online && proto != null && proto != RelayConstants.protoVersion;
+  /// Null while unknown (offline, or no version given).
+  VersionFit? get fit {
+    final min = protoMin, max = protoMax;
+    if (!online || min == null || max == null) return null;
+    return versionFit(min, max);
+  }
+
+  /// True when the server and this app have no version in common.
+  bool get needsUpdate => fit != null && fit != VersionFit.ok;
+
+  /// The server's own name for people ('' for the dedicated server's
+  /// default `server`).
+  String get label => name.isNotEmpty && name != 'server' ? name : '';
 
   /// Lenient parse of `GET /health`; anything unexpected reads as offline.
   static ServerHealth parse(String body) {
@@ -37,9 +72,12 @@ class ServerHealth {
       final j = jsonDecode(body);
       if (j is! Map || j['ok'] != true) return const ServerHealth.offline();
       final name = j['name'], proto = j['proto'], viewers = j['viewers'], version = j['version'];
+      final min = j['protoMin'], max = j['protoMax'];
+      final p = proto is num ? proto.toInt() : null;
       return ServerHealth.online(
         name: name is String ? name.trim() : '',
-        proto: proto is num ? proto.toInt() : null,
+        protoMin: min is num ? min.toInt() : p,
+        protoMax: max is num ? max.toInt() : p,
         viewers: viewers is num ? viewers.toInt() : 0,
         version: version is String ? version.trim() : '',
       );
@@ -49,6 +87,26 @@ class ServerHealth {
   }
 }
 
+/// The version gate's message for a server that does not fit: who has
+/// to update, in plain words ("Bob's server runs Starsync 1.2.1 — they
+/// need to update").
+String versionGateText(ServerHealth h) {
+  final who = h.label.isNotEmpty ? h.label : 'The server';
+  final runs = h.version.isNotEmpty ? '$who runs Starsync ${h.version}' : '$who runs ${h.fit == VersionFit.youUpdate ? 'a newer' : 'an older'} Starsync';
+  return h.fit == VersionFit.youUpdate ? '$runs — you need to update' : '$runs — they need to update';
+}
+
+/// A join stopped before connecting: the server and this app have no
+/// version in common ([versionGateText]). [youUpdate]: this app is the
+/// older one, so the updater can help.
+class VersionGateRefused implements Exception {
+  final String message;
+  final bool youUpdate;
+  const VersionGateRefused(this.message, {required this.youUpdate});
+  @override
+  String toString() => message;
+}
+
 Uri healthUri(String host, String port) {
   final h = host.trim();
   // Bare IPv6 literals need brackets in a URL.

apps/desktop/lib/src/screens/home/settings_page.dart

@@ -1,7 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:signals/signals_flutter.dart';
 
-import '../../state/session_state.dart';
+import '../../app/app_graph.dart';
 import '../../state/settings.dart';
 import '../../update/update_controller.dart';
 import 'ui.dart';
@@ -88,10 +88,11 @@ class SettingsHintCard extends StatelessWidget {
 class CustomShaderFiles extends StatelessWidget {
   const CustomShaderFiles({super.key});
 
-  Future<void> _addFiles() async {
+  Future<void> _addFiles(BuildContext context) async {
+    final folders = AppScope.of(context).ports.folders;
     final List<String> files;
     try {
-      files = await SessionState.instance.ports.folders.pickFiles(
+      files = await folders.pickFiles(
         dialogTitle: 'Pick mpv GLSL shaders',
         extensions: const ['glsl', 'hook'],
       );
@@ -123,7 +124,7 @@ class CustomShaderFiles extends StatelessWidget {
                     style: muted),
               ),
               TextButton.icon(
-                onPressed: _addFiles,
+                onPressed: () => _addFiles(context),
                 icon: const Icon(Icons.add, size: 18),
                 label: const Text('Add .glsl files'),
               ),

apps/desktop/lib/src/session/auto_sit_out.dart

@@ -89,7 +89,7 @@ class AutoSitOut {
 
   /// Once a second. [self]: this member's presence in the latest state
   /// (null: not in one); [alone]: nobody else connected ([isAlone]);
-  /// [enabled]: the setting (and not a solo session).
+  /// [enabled]: the setting.
   AutoSitOutStep tick(DateTime now,
       {required Presence? self, required bool playing, required bool alone, required bool enabled}) {
     if (playing) _lastActive = now;

apps/desktop/lib/src/session/connection.dart

@@ -142,7 +142,8 @@ final class ConnReconnecting extends ConnState {
 }
 
 /// The server refused this app; nothing retries. [code]: `version` or
-/// `secret` when the server said so, else empty (offline, timeout,
+/// `secret` when the server said so, `closed` when the host stopped
+/// sharing (close 4016), else empty (offline, timeout,
 /// anything else on the first dial); [message]: in plain words
 /// ([connectErrorText]).
 final class ConnRefused extends ConnState {
@@ -166,6 +167,10 @@ final class ConnReplaced extends ConnState {
 /// [ConnReplaced] in plain words.
 const replacedText = 'Starsync was opened in another window';
 
+/// `ConnRefused('closed')`: the host closed their server to friends
+/// (close 4016).
+const stoppedSharingText = 'the host stopped sharing their server';
+
 /// A version refusal in plain words: [err] is the server's `err`
 /// `version` (its range in `min`/`max`), or a proto 15 server's codeless
 /// `proto mismatch`, which is always an older host.
@@ -518,6 +523,8 @@ class Connection {
         _end(ConnRefused('version', versionText(null)));
       case CloseCodes.secret:
         _end(const ConnRefused('secret', 'wrong server password (401)'));
+      case CloseCodes.closed:
+        _end(const ConnRefused('closed', stoppedSharingText));
       default:
         _dropped(now());
     }

apps/desktop/lib/src/session/identity.dart

@@ -9,7 +9,6 @@ import 'package:signals/signals_flutter.dart';
 import 'package:sync_relay_core/core.dart' show validClientId;
 
 import '../state/connect_prefs.dart';
-import '../state/session_state.dart';
 import '../state/settings.dart' show settingsBoxName;
 import '../widgets/avatar_pipeline.dart';
 
@@ -96,17 +95,11 @@ const _keyColor = 'profileColor';
 /// avatar = removed). Swappable so tests can watch it.
 typedef ProfilePush = void Function({String? name, String? avatar});
 
-/// The one place a profile change reaches the server.
-void pushProfileToSession({String? name, String? avatar}) {
-  final session = SessionState.instance;
-  if (session.route.peek() != AppRoute.session) return;
-  session.coordinator.updateProfile(name: name, avatar: avatar);
-}
-
-/// Display name, picture and colour of this app's user. Backed by
-/// [SessionState.lastForm] (name) and the connect-form box (the cropped
+/// Display name, picture and colour of this app's user. Backed by the
+/// connect form ([forms]: the name) and the connect-form box (the cropped
 /// 256 px PNG and the colour); every change is persisted, and while in a
-/// server it is pushed through [push] so everyone sees it at once.
+/// server it is pushed through [push] so everyone sees it at once. The
+/// composition root sets both.
 class Profile {
   static final Profile instance = Profile._();
   Profile._();
@@ -116,7 +109,8 @@ class Profile {
   final picture = signal<Uint8List?>(null);
   final color = signal<Color>(profileColors.first);
   final error = signal<String?>(null);
-  ProfilePush push = pushProfileToSession;
+  ProfilePush push = ({String? name, String? avatar}) {};
+  ConnectStore forms = ConnectStore();
   bool _loaded = false;
   Timer? _nameTimer;
 
@@ -131,7 +125,7 @@ class Profile {
   }
 
   Future<void> _load() async {
-    final form = SessionState.instance.lastForm;
+    final form = forms.form;
     name.value = form.name;
     try {
       final box = connectFormBoxIfOpen() ?? await openConnectFormBox();
@@ -162,7 +156,7 @@ class Profile {
     final v = value.trim();
     if (v.isEmpty || v == name.peek()) return;
     name.value = v;
-    SessionState.instance.lastForm.name = v;
+    forms.form.name = v;
     unawaited(_save());
     // Typing renames once it settles, not on every key.
     _nameTimer?.cancel();
@@ -187,7 +181,7 @@ class Profile {
 
   Future<void> _save() async {
     try {
-      await SessionState.instance.saveForm();
+      await forms.save();
       final box = connectFormBoxIfOpen() ?? await openConnectFormBox();
       final png = picture.peek();
       await box.putAll({

apps/desktop/lib/src/session/invite.dart

@@ -0,0 +1,123 @@
+import 'dart:io';
+
+import 'package:flutter/foundation.dart' show debugPrint;
+
+/// What a friend needs to join your server: where ([host], [port]), what
+/// it is called ([name]), whether it asks a password ([password]; the
+/// password itself is never in it) and which Starsync runs it
+/// ([version]). [fp]: reserved for a pinned certificate fingerprint
+/// (`wss://` with a self-signed certificate); always null for now.
+class Invite {
+  final String host;
+  final int port;
+  final String name;
+  final bool password;
+  final String version;
+  final String? fp;
+  const Invite({
+    required this.host,
+    required this.port,
+    this.name = '',
+    this.password = false,
+    this.version = '',
+    this.fp,
+  });
+
+  /// What goes in the Join card's address and port.
+  String get address => '${host.contains(':') ? '[$host]' : host}:$port';
+
+  /// The text Invite copies: the address, whether to ask for the password,
+  /// the version to match.
+  String get text => [
+        'Join me on Starsync: $address',
+        if (password) '(ask me for the password)',
+        if (version.isNotEmpty) '· Starsync $version',
+      ].join(' ');
+
+  @override
+  bool operator ==(Object other) =>
+      other is Invite &&
+      other.host == host &&
+      other.port == port &&
+      other.name == name &&
+      other.password == password &&
+      other.version == version &&
+      other.fp == fp;
+
+  @override
+  int get hashCode => Object.hash(host, port, name, password, version, fp);
+
+  @override
+  String toString() => 'Invite($address${password ? ', password' : ''})';
+}
+
+/// The `host:port` in a pasted invite (or a bare address); null when
+/// there is none.
+({String host, String port})? addressIn(String text) {
+  final m = RegExp(r'(\[[0-9a-fA-F:]+\]|[A-Za-z0-9.-]+):(\d{1,5})\b').firstMatch(text);
+  if (m == null) return null;
+  final host = m.group(1)!;
+  return (host: host.startsWith('[') ? host.substring(1, host.length - 1) : host, port: m.group(2)!);
+}
+
+/// Interface names of container and VM bridges, never a way in for a
+/// friend (Docker, Podman, libvirt, LXC, VirtualBox, VMware, WSL/Hyper-V).
+final _virtualName = RegExp(
+    r'^(docker|br-|veth|virbr|vmnet|vboxnet|cni|flannel|podman|lxcbr|lxdbr|vEthernet|VirtualBox|VMware)',
+    caseSensitive: false);
+
+/// The proxy fake-IP range (198.18.0.0/15, benchmarking space that TUN
+/// proxies like Clash hand out): this machine's address on it is useless
+/// to anyone else.
+bool isFakeIp(List<int> b) => b[0] == 198 && (b[1] == 18 || b[1] == 19);
+
+bool _isPrivate(List<int> b) =>
+    b[0] == 10 || (b[0] == 192 && b[1] == 168) || (b[0] == 172 && b[1] >= 16 && b[1] < 32);
+
+/// Shared address space (100.64.0.0/10): mesh VPNs like Tailscale.
+bool _isShared(List<int> b) => b[0] == 100 && b[1] >= 64 && b[1] < 128;
+
+/// The addresses of [interfaces] a friend could dial, best first: IPv4,
+/// no loopback, link-local or fake-IP address, no container or VM bridge;
+/// home networks (192.168, then 10, then 172.16/12) first, then a mesh
+/// VPN's, then anything else (a public address). No repeats.
+List<String> inviteAddresses(Iterable<({String name, InternetAddress address})> interfaces) {
+  int rank(List<int> b) => b[0] == 192 && b[1] == 168
+      ? 0
+      : _isPrivate(b)
+          ? 1
+          : _isShared(b)
+              ? 2
+              : 3;
+  final usable = [
+    for (final i in interfaces)
+      if (i.address.type == InternetAddressType.IPv4 &&
+          !i.address.isLoopback &&
+          !i.address.isLinkLocal &&
+          !(i.address.rawAddress[0] == 169 && i.address.rawAddress[1] == 254) &&
+          !isFakeIp(i.address.rawAddress) &&
+          !_virtualName.hasMatch(i.name))
+        i.address,
+  ];
+  final indexed = [for (var n = 0; n < usable.length; n++) (n, usable[n])];
+  indexed.sort((a, b) {
+    final r = rank(a.$2.rawAddress).compareTo(rank(b.$2.rawAddress));
+    return r != 0 ? r : a.$1.compareTo(b.$1);
+  });
+  return {for (final (_, a) in indexed) a.address}.toList();
+}
+
+/// This machine's interfaces as [inviteAddresses] takes them (empty when
+/// they can't be listed).
+Future<List<({String name, InternetAddress address})>> machineInterfaces() async {
+  try {
+    final list = await NetworkInterface.list(type: InternetAddressType.IPv4);
+    return [
+      for (final i in list)
+        for (final a in i.addresses) (name: i.name, address: a),
+    ];
+  } catch (e) {
+    debugPrint('list network interfaces failed: $e');
+    return const [];
+  }
+}

apps/desktop/lib/src/session/navigation.dart

@@ -0,0 +1,194 @@
+import 'dart:async';
+
+import 'package:flutter/foundation.dart' show debugPrint;
+import 'package:signals/signals.dart';
+import 'package:sync_relay_core/core.dart';
+
+import '../screens/home/health_probe.dart';
+import '../state/connect_prefs.dart';
+import 'app_events.dart' show ActionFailed, ServerRefused;
+import 'connection.dart';
+import 'identity.dart' show Profile;
+import 'session_coordinator.dart';
+import 'your_server.dart';
+
+/// Which server this app is in.
+enum Place {
+  /// None yet (starting, or between two servers).
+  none,
+
+  /// Your own server ([YourServer]): home.
+  yours,
+
+  /// A friend's (joined from the Join card).
+  friend,
+}
+
+/// A join that did not get as far as connecting, in plain words.
+class JoinFailed implements Exception {
+  final String message;
+  const JoinFailed(this.message);
+  @override
+  String toString() => message;
+}
+
+/// Where this app is: home on your own server, or in a friend's. It
+/// starts the app at home, switches to a friend's server on a join (after
+/// the version gate) and back home when you leave theirs, a join fails or
+/// they stop sharing. Your server stays up all the while; you leave it
+/// (with `bye`) while you are away. Made by the composition root.
+class Navigation {
+  Navigation({
+    required this.coordinator,
+    required this.yourServer,
+    required this.forms,
+    this.profile,
+    this.healthGet = defaultHealthGet,
+  }) {
+    yourServer.onCrash = () {
+      if (place.peek() != Place.friend) unawaited(goHome());
+    };
+    // A friend closed their server to friends: back home, and say so.
+    _stops.add(effect(() {
+      final s = coordinator.connection.state.value;
+      if (s is ConnRefused && s.code == 'closed' && untracked(() => place.value) == Place.friend) {
+        // Said once home (a connect clears the toasts).
+        scheduleMicrotask(() => unawaited(goHome().then(
+            (_) => coordinator.notify(const ServerRefused('The host stopped sharing their server')))));
+      }
+    }));
+  }
+
+  final SessionCoordinator coordinator;
+  final YourServer yourServer;
+  final ConnectStore forms;
+  /// Name and picture for your own connection (default: the app's).
+  final Profile? profile;
+  final HealthGetter healthGet;
+  final _stops = <void Function()>[];
+
+  Profile get _me => profile ?? Profile.instance;
+
+  final place = signal(Place.none);
+
+  /// In a server (yours or a friend's).
+  late final Computed<bool> online = computed(() => place.value != Place.none);
+
+  /// On your own server.
+  late final Computed<bool> home = computed(() => place.value == Place.yours);
+
+  /// A friend's server's own name (`/health`), '' for yours, until known
+  /// or when it only has the default name.
+  final serverLabel = signal('');
+
+  /// The server's Starsync version: yours is this app's; a friend's
+  /// comes from its `/health`; '' until known.
+  final serverVersion = signal('');
+
+  /// The address dialled for a friend's server ("host:port"), '' at home.
+  final address = signal('');
+
+  // Bumped by every move; a superseded one stops at its next step.
+  int _op = 0;
+
+  /// The app starts: home, on your own server.
+  Future<void> start() => goHome();
+
+  /// To your own server (started if it is not running). False when it
+  /// could not start or the move was superseded; the reason is a notice.
+  Future<bool> goHome() async {
+    final op = ++_op;
+    _arrive(Place.none);
+    try {
+      await _me.ensureLoaded();
+      final name = _me.name.peek().trim();
+      final port = await yourServer.start(name: name);
+      if (op != _op) return false;
+      coordinator.hostFile = yourServer.setFile;
+      await coordinator.connect(ConnectParams(
+        host: '127.0.0.1',
+        port: port,
+        secret: '',
+        name: name.isEmpty ? 'Me' : name,
+        avatar: _me.avatarBase64(),
+        hostKey: yourServer.hostKey,
+      ));
+      if (op != _op) return false;
+      serverVersion.value = appVersion;
+      _arrive(Place.yours);
+      return true;
+    } on ConnectCancelled {
+      return false;
+    } catch (e, st) {
+      debugPrint('your server: $e\n$st');
+      if (op == _op) coordinator.notify(ActionFailed("couldn't start your server: $e"));
+      return false;
+    }
+  }
+
+  void _arrive(Place p) {
+    if (p != Place.yours) coordinator.hostFile = null;
+    if (p == Place.none) {
+      serverLabel.value = '';
+      serverVersion.value = '';
+      address.value = '';
+    }
+    place.value = p;
+  }
+
+  /// Joins a friend's server. The version gate first (`/health`): an
+  /// unreachable server or one without a version in common stops here,
+  /// still at home ([JoinFailed], [VersionGateRefused]). Then you leave
+  /// your server and connect; when that fails you are back home and the
+  /// error is rethrown (a refusal: [HelloRefused]).
+  Future<void> join(ConnectParams params) async {
+    final op = ++_op;
+    final health = await probeHealth(params.host, '${params.port}', healthGet);
+    if (op != _op) throw const ConnectCancelled();
+    if (!health.online) throw const JoinFailed('host offline — check address and port');
+    final fit = health.fit;
+    if (fit != null && fit != VersionFit.ok) {
+      throw VersionGateRefused(versionGateText(health), youUpdate: fit == VersionFit.youUpdate);
+    }
+    _arrive(Place.none);
+    try {
+      await coordinator.connect(params);
+      if (op != _op) throw const ConnectCancelled();
+    } catch (_) {
+      if (op == _op) unawaited(goHome());
+      rethrow;
+    }
+    serverLabel.value = health.label;
+    serverVersion.value = health.version;
+    address.value = '${params.host}:${params.port}';
+    _arrive(Place.friend);
+    await forms.remember(RecentServer(host: params.host, port: '${params.port}', secret: params.secret));
+  }
+
+  /// The Join card's Cancel: stops a join under way; when it had already
+  /// left home, back home.
+  Future<void> cancelPending() async {
+    _op++;
+    try {
+      await coordinator.cancelConnect();
+    } catch (_) {}
+    if (place.peek() != Place.yours) await goHome();
+  }
+
+  /// Out of a friend's server (Leave): back home.
+  Future<bool> leaveFriend() => goHome();
+
+  /// The app closes: out of whichever server ([bye] false: Update and
+  /// restart, the member stays `gone` for the restarted app).
+  Future<void> leave({bool bye = true}) async {
+    _op++;
+    await coordinator.leave(bye: bye);
+    _arrive(Place.none);
+  }
+
+  void dispose() {
+    for (final stop in _stops) {
+      stop();
+    }
+  }
+}

apps/desktop/lib/src/session/session_coordinator.dart

@@ -268,9 +268,12 @@ class SessionCoordinator {
   StreamSubscription? _nudgeSub;
   StreamSubscription? _errSub;
 
-  /// A solo session (set by SessionState): no auto sit-out, there is
-  /// nobody to hold up.
-  bool solo = false;
+  /// Nobody else is in the server (D9): a plain player, Play rather than
+  /// Ready, links go up direct. Also true before the first state.
+  late final Computed<bool> alone = computed(() {
+    final r = serverState.value;
+    return r == null || aloneIn(r.members, connection.memberId);
+  });
   bool _playerReady = false;
   bool _wasPlayAllowed = false;
   // Last ready flag the server reported for self; sent again when a
@@ -316,10 +319,6 @@ class SessionCoordinator {
   final memberNames = MemberNames();
   // The media this member was told its upload is too slow for.
   int _slowWarnedFor = -1;
-  /// What this client put up last in this connection (a solo session
-  /// carries it over when it becomes a hosted server).
-  PickedMedia? get lastPick => _lastPick;
-  PickedMedia? _lastPick;
   // Server seek applied to the player (event id and when), checked once it
   // should have landed.
   int? _pendingSeekEvent;
@@ -548,7 +547,6 @@ class SessionCoordinator {
     _seekGate.reset();
     _clearPendingSeek();
     _lastEventId = -1;
-    _lastPick = null;
     _resetJellyfin();
     _jfToastShown = false;
     if (!_jellyfinListening) {
@@ -1152,7 +1150,7 @@ class SessionCoordinator {
         self: online ? selfMember.peek()?.presence : null,
         playing: r?.transport == 'playing',
         alone: r == null || aloneIn(r.members, connection.memberId),
-        enabled: !solo && AppSettings.instance.autoSitOut.peek());
+        enabled: AppSettings.instance.autoSitOut.peek());
     switch (step) {
       case AutoAway(:final reason):
         _log.info('auto sit-out: away (${reason.name})');
@@ -1475,7 +1473,6 @@ class SessionCoordinator {
   Future<String?> swapLink(String url,
       {LinkRelay relay = LinkRelay.direct, bool anyway = false, String? queueId}) async {
     markInput();
-    _lastPick = LinkMedia(url, relay: relay, anyway: anyway);
     final media = await mediaForLink(jellyfin, url);
     if (media.jellyfin != null) {
       _pendingOrigin = _JellyfinOrigin(url);
@@ -1557,7 +1554,6 @@ class SessionCoordinator {
   /// relayed by this member for viewers without an account.
   void swapJellyfin(JellyfinMedia media, {String? queueId}) {
     markInput();
-    _lastPick = media;
     _pendingOrigin = const _JellyfinOrigin(null);
     _swap(mediaForPick(media).copyWith(relay: const MediaRelay()), queueId: queueId);
   }
@@ -1567,7 +1563,6 @@ class SessionCoordinator {
   /// when sent.
   Future<String?> swapFile(String path, {String? queueId}) async {
     markInput();
-    _lastPick = FileMedia(path);
     final host = hostFile;
     if (host != null) {
       final file = await host(path);

apps/desktop/lib/src/session/your_server.dart

@@ -0,0 +1,207 @@
+import 'dart:async';
+import 'dart:convert';
+import 'dart:io' show InternetAddress;
+import 'dart:math';
+
+import 'package:flutter/foundation.dart' show debugPrint, visibleForTesting;
+import 'package:signals/signals.dart';
+import 'package:sync_relay_core/core.dart';
+
+import '../jellyfin/accounts.dart';
+import '../jellyfin/session_media.dart' show relayCredentialFor;
+import '../state/connect_prefs.dart';
+import '../state/server_isolate.dart';
+import 'invite.dart';
+
+/// A fresh key per app run: this app's own client sends it in hello to be
+/// recognised as the host (`members[].host`; it also stands in for the
+/// password).
+String newHostKey() {
+  final r = Random.secure();
+  return base64Url.encode([for (var i = 0; i < 24; i++) r.nextInt(256)]);
+}
+
+/// Starts the server isolate (tests may pass their own).
+typedef ServerStarter = Future<ServerIsolate> Function(
+  AppConfig config, {
+  bool loopbackOnly,
+  String? logDir,
+  required void Function(String line) onLog,
+  required void Function(String error) onCrash,
+});
+
+Future<ServerIsolate> _startIsolate(
+  AppConfig config, {
+  bool loopbackOnly = false,
+  String? logDir,
+  required void Function(String line) onLog,
+  required void Function(String error) onCrash,
+}) =>
+    ServerIsolate.start(config, loopbackOnly: loopbackOnly, logDir: logDir, onLog: onLog, onCrash: onCrash);
+
+/// "Your server": the one server this app runs for its whole life (a
+/// [ServerIsolate] running `serve`). It starts on 127.0.0.1 and a free
+/// port, so only this app reaches it; [invite] attaches a second
+/// listener on every interface at the configured port (Settings → Party
+/// & network: port and password) and [stopSharing] detaches it. Members,
+/// what plays and Up next never restart or reconnect for either. Made
+/// by the composition root.
+class YourServer {
+  YourServer({
+    required this.forms,
+    this.jellyfin,
+    Future<String> Function()? ytDlpDir,
+    String? Function()? logDir,
+    ServerStarter? starter,
+    Future<List<({String name, InternetAddress address})>> Function()? interfaces,
+  })  : _ytDlpDir = ytDlpDir ?? (() async => ''),
+        _logDir = logDir ?? (() => null),
+        _starter = starter ?? _startIsolate,
+        _interfaces = interfaces ?? machineInterfaces;
+
+  final ConnectStore forms;
+  /// Linked Jellyfin servers (default: the app's): the relay login.
+  final JellyfinAccounts? jellyfin;
+  final Future<String> Function() _ytDlpDir;
+  final String? Function() _logDir;
+  final ServerStarter _starter;
+  final Future<List<({String name, InternetAddress address})>> Function() _interfaces;
+
+  /// Sent by this app's own client (see [newHostKey]).
+  final String hostKey = newHostKey();
+
+  /// The loopback port while it runs; null before [start] and after
+  /// [stop] or a crash.
+  final port = signal<int?>(null);
+
+  /// The invite while shared (the listener attached); null when only this
+  /// app can reach it.
+  final shared = signal<Invite?>(null);
+
+  /// An [invite] or [stopSharing] is under way.
+  final busy = signal(false);
+
+  /// Set when the server died without being stopped; the shell says so
+  /// and clears it. The next [start] makes a new one.
+  final crash = signal<String?>(null);
+
+  /// Called after a crash (the navigation reconnects home).
+  void Function()? onCrash;
+
+  ServerIsolate? _server;
+  Future<int>? _starting;
+
+  @visibleForTesting
+  ServerIsolate? get server => _server;
+
+  JellyfinAccounts get _accounts => jellyfin ?? JellyfinAccounts.instance;
+
+  /// Starts it once (later calls get the same port); a new one after a
+  /// crash. [name]: what `/health` calls it ("Bob's server").
+  Future<int> start({String name = ''}) {
+    final running = _server;
+    if (running != null && running.isRunning) return Future.value(running.port);
+    return _starting ??= _start(name).whenComplete(() => _starting = null);
+  }
+
+  Future<int> _start(String name) async {
+    final who = name.trim();
+    late final ServerIsolate server;
+    server = await _starter(
+      AppConfig(
+        port: 0,
+        secret: '',
+        name: who.isEmpty ? 'server' : "$who's server",
+        hostKey: hostKey,
+        ytDlpDir: await _ytDlpDir(),
+      ),
+      loopbackOnly: true,
+      // Its session log (every member's shared diagnostics and its own
+      // records) goes next to the app's.
+      logDir: _logDir(),
+      // Its records join the app's log as `server.<logger>`.
+      onLog: (line) => relogLine('server', line),
+      onCrash: (cause) => _onCrash(server, cause),
+    );
+    _server = server;
+    port.value = server.port;
+    return server.port;
+  }
+
+  void _onCrash(ServerIsolate server, String cause) {
+    if (!identical(_server, server)) return;
+    _server = null;
+    port.value = null;
+    shared.value = null;
+    final message = 'server crashed: $cause';
+    debugPrint('[server] $message');
+    crash.value = message;
+    onCrash?.call();
+  }
+
+  /// Opens it to friends (attaching the network listener if it is not
+  /// yet) and returns the invite to hand out. Throws when the port can't
+  /// be opened (in use) or the server is not running.
+  Future<Invite> invite() async {
+    final server = _server;
+    if (server == null || !server.isRunning) throw StateError('your server is not running');
+    final current = shared.peek();
+    if (current != null) return current;
+    busy.value = true;
+    try {
+      final form = forms.form;
+      final want = int.tryParse(form.hostPort.trim()) ?? 8080;
+      await _accounts.ensureLoaded(validate: false);
+      final bound = await server.share(
+        port: want,
+        secret: form.hostSecret,
+        // Guests without an account watch Jellyfin items through the
+        // server, with this app's own sign-in.
+        jellyfin: relayCredentialFor(_accounts),
+      );
+      final invite = await inviteFor(bound, password: form.hostSecret.isNotEmpty);
+      shared.value = invite;
+      return invite;
+    } finally {
+      busy.value = false;
+    }
+  }
+
+  /// The invite for [port] from this machine's best address (see
+  /// [inviteAddresses]); 127.0.0.1 when there is none.
+  Future<Invite> inviteFor(int port, {required bool password}) async {
+    final addresses = inviteAddresses(await _interfaces());
+    return Invite(
+      host: addresses.isEmpty ? '127.0.0.1' : addresses.first,
+      port: port,
+      password: password,
+      version: appVersion,
+    );
+  }
+
+  /// Closes it to friends again: everyone but you leaves (told, so their
+  /// apps do not retry); you, what plays and Up next stay.
+  Future<void> stopSharing() async {
+    final server = _server;
+    if (server == null || shared.peek() == null) return;
+    busy.value = true;
+    try {
+      await server.unshare();
+      shared.value = null;
+    } finally {
+      busy.value = false;
+    }
+  }
+
+  /// Makes [path] the hosted file (a File put up here; `/m` serves it).
+  Future<({String name, int size})?> setFile(String path) async => _server?.setFile(path);
+
+  /// The app closes: the server stops (sockets closed, port freed).
+  Future<void> stop() async {
+    final server = _server;
+    _server = null;
+    port.value = null;
+    shared.value = null;
+    await server?.stop();
+  }
+}

apps/desktop/lib/src/shell/app_shell.dart

@@ -14,18 +14,18 @@ import '../jellyfin/browse_scope.dart' show BrowseStart;
 import '../jellyfin/session_media.dart';
 import '../screens/home/connect_flow.dart';
 import '../session/app_events.dart' show ActionFailed, ScheduleResult;
-import '../session/session_coordinator.dart' show ConnectParams;
 import '../screens/home/health_probe.dart';
 import '../screens/home/media_picker.dart';
 import '../session/identity.dart';
 import '../screens/home/update_indicator.dart';
-import '../state/session_state.dart';
+import '../app/app_graph.dart';
+import '../session/navigation.dart' show Place;
 import '../state/settings.dart';
 import '../update/update_controller.dart';
 import 'chat_panel.dart';
 import 'connect_cards.dart';
 import 'handoff.dart';
-import 'library_link.dart' show LinkProber, defaultLinkProber;
+import 'library_link.dart' show LinkProber;
 import 'library_tab.dart';
 import 'motion.dart';
 import 'party_strip.dart';
@@ -38,7 +38,8 @@ import 'welcome.dart';
 
 /// The one window: the party strip over a body that fades through between
 /// the tabs and the full player, the floating mini player, the chat panel
-/// and the toasts. Online/offline follows [SessionState.route].
+/// and the toasts. Where the app is (your server, a friend's) follows
+/// [Navigation.place].
 ///
 /// The player ([SessionPlayer], the only `Video`) lives in one layer of
 /// the body: full it fills the body (fullscreen: the window, strip
@@ -61,7 +62,7 @@ class AppShell extends StatefulWidget {
   final VideoViewBuilder? videoBuilder;
   /// What the Library's Link page asks about a link (tests: a fake, so no
   /// network or yt-dlp runs).
-  final LinkProber linkProbe;
+  final LinkProber? linkProbe;
   const AppShell({
     super.key,
     this.updates,
@@ -70,7 +71,7 @@ class AppShell extends StatefulWidget {
     this.healthGet = defaultHealthGet,
     this.jellyfin,
     this.videoBuilder,
-    this.linkProbe = defaultLinkProber,
+    this.linkProbe,
   });
 
   @override
@@ -112,9 +113,9 @@ class AppShellState extends State<AppShell> with SingleTickerProviderStateMixin
   bool _dragging = false;
   bool _handoffOpen = false;
 
-  final _flow = ConnectFlow();
-  late final _join = JoinFields(SessionState.instance.lastForm);
-  late final _host = HostFields(SessionState.instance.lastForm);
+  late final AppGraph _graph = AppScope.of(context);
+  late final _flow = ConnectFlow(navigation: _graph.navigation, forms: _graph.forms);
+  late final _join = JoinFields(_graph.forms.form);
   late final JellyfinAccounts _jellyfin = widget.jellyfin ?? JellyfinAccounts.instance;
   late MediaPickerController _picker = _newPicker();
   BrowseStart? _libraryStart;
@@ -126,22 +127,17 @@ class AppShellState extends State<AppShell> with SingleTickerProviderStateMixin
   bool _dialogOpen = false;
   final _stops = <void Function()>[];
   // Rebuild the shell on these flips, not on every state broadcast.
-  final _online = computed(() => SessionState.instance.route.value == AppRoute.session);
-  /// Nobody else watches: offline, solo, or solo becoming a server.
-  final _alone = computed(() {
-    final s = SessionState.instance;
-    return s.route.value != AppRoute.session || s.solo.value || s.switching.value;
-  });
-  final _hasMedia = computed(() =>
-      SessionState.instance.route.value == AppRoute.session &&
-      SessionState.instance.coordinator.serverState.value?.media != null);
+  late final _online = computed(() => _graph.navigation.online.value);
+  /// Nobody else is in the server (D9): a plain player.
+  late final _alone = computed(() => !_graph.navigation.online.value || _graph.coordinator.alone.value);
+  late final _hasMedia =
+      computed(() => _graph.navigation.online.value && _graph.coordinator.serverState.value?.media != null);
 
   /// A video is on in the session (not finished): the update bar stays
   /// off the full player.
-  final _watching = computed(() {
-    final s = SessionState.instance;
-    final r = s.coordinator.serverState.value;
-    return s.route.value == AppRoute.session && r?.media != null && r?.transport != 'finished';
+  late final _watching = computed(() {
+    final r = _graph.coordinator.serverState.value;
+    return _graph.navigation.online.value && r?.media != null && r?.transport != 'finished';
   });
 
   PlayerMode get mode => _mode;
@@ -149,7 +145,7 @@ class AppShellState extends State<AppShell> with SingleTickerProviderStateMixin
   bool get fullscreen => _fullscreen;
 
   MediaPickerController _newPicker({JellyfinMedia? jellyfin, MediaKind? source}) {
-    final f = SessionState.instance.lastForm;
+    final f = _graph.forms.form;
     final c = MediaPickerController(mediaPath: f.mediaPath, linkUrl: f.linkUrl, jellyfin: jellyfin, source: source);
     if (jellyfin == null) unawaited(restoreLastPick(c, _jellyfin, () => mounted && identical(c, _picker)));
     return c;
@@ -163,14 +159,16 @@ class AppShellState extends State<AppShell> with SingleTickerProviderStateMixin
     _jellyfin.ensureLoaded();
     if (widget.autoUpdateCheck) _autoCheck();
     HardwareKeyboard.instance.addHandler(_onKey);
-    final session = SessionState.instance;
-    final coord = session.coordinator;
+    final nav = _graph.navigation;
+    final coord = _graph.coordinator;
     _feedSeen = coord.feedLog.peek().length;
     _stops.add(effect(() {
-      final online = session.route.value == AppRoute.session;
+      final place = nav.place.value;
+      final online = place != Place.none;
       // Set now, not later: the media effect below may run first in this
-      // same flush, and its scheduled show reads these.
-      _autoFull = online;
+      // same flush, and its scheduled show reads these. A friend's video
+      // opens full; back home, yours waits in the mini player.
+      _autoFull = place == Place.friend;
       if (!online) _lastMediaId = -1;
       untracked(() => _later(() => online ? _wentOnline() : _wentOffline()));
     }));
@@ -178,7 +176,7 @@ class AppShellState extends State<AppShell> with SingleTickerProviderStateMixin
     // after joining or a put-up of ours, else as the mini player).
     _stops.add(effect(() {
       final r = coord.serverState.value;
-      final online = session.route.value == AppRoute.session;
+      final online = nav.online.value;
       if (!online || r == null || r.media == null) return;
       if (r.mediaId == _lastMediaId) return;
       _lastMediaId = r.mediaId;
@@ -218,31 +216,21 @@ class AppShellState extends State<AppShell> with SingleTickerProviderStateMixin
     var wasOut = false;
     _stops.add(effect(() {
       final out = coord.selfAway.value;
-      if (wasOut && !out && session.route.peek() == AppRoute.session) {
+      if (wasOut && !out && nav.online.peek()) {
         _later(() {
           if (_mode == PlayerMode.none) _show(PlayerMode.mini);
         });
       }
       wasOut = out;
     }));
-    // Solo becoming a hosted server: the player closes while the media
-    // moves over and comes back the way it was once it is up again.
+    // Your server died (the navigation starts a new one): say so.
+    final yours = _graph.yourServer;
     _stops.add(effect(() {
-      if (!session.switching.value) return;
-      _later(() {
-        _lastMediaId = -1;
-        _autoFull = _mode == PlayerMode.full;
-        if (_fullscreen) _toggleFullscreen();
-        _show(PlayerMode.none);
-      });
-    }));
-    // The hosted server died mid-session (SessionState leaves): say so.
-    _stops.add(effect(() {
-      final crash = session.serverCrash.value;
+      final crash = yours.crash.value;
       if (crash == null) return;
       _later(() {
-        session.serverCrash.value = null;
-        _alert('Server crashed', crash);
+        yours.crash.value = null;
+        _alert('Your server crashed', '$crash\n\nA new one starts; anyone who was in it joins again.');
       });
     }));
   }
@@ -261,7 +249,6 @@ class AppShellState extends State<AppShell> with SingleTickerProviderStateMixin
     _watching.dispose();
     _flow.dispose();
     _join.dispose();
-    _host.dispose();
     _picker.dispose();
     _chat.dispose();
     _chatFocus.dispose();
@@ -291,8 +278,8 @@ class AppShellState extends State<AppShell> with SingleTickerProviderStateMixin
 
   void _wentOnline() {
     _unread = 0;
-    _feedSeen = SessionState.instance.coordinator.feedLog.peek().length;
-    // Hosting starts with nothing up: the library is where to pick it.
+    _feedSeen = _graph.coordinator.feedLog.peek().length;
+    // A new server: the library is where to pick something.
     setState(() => _tab = ShellTab.library);
   }
 
@@ -338,7 +325,7 @@ class AppShellState extends State<AppShell> with SingleTickerProviderStateMixin
   /// The player's ×: sit out (stay in the server, nothing loaded; the
   /// player shows the join-back card). Once out, × closes the player.
   void _closePlayer() {
-    final coord = SessionState.instance.coordinator;
+    final coord = _graph.coordinator;
     if (coord.selfAway.peek()) {
       _show(PlayerMode.none);
     } else {
@@ -349,7 +336,7 @@ class AppShellState extends State<AppShell> with SingleTickerProviderStateMixin
   Future<void> _setWindowFullscreen(bool on) async {
     if (!widget.windowControls) return;
     try {
-      await SessionState.instance.ports.shell.setFullScreen(on);
+      await _graph.ports.shell.setFullScreen(on);
     } catch (_) {
       // No window manager.
     }
@@ -384,7 +371,7 @@ class AppShellState extends State<AppShell> with SingleTickerProviderStateMixin
   /// "Change video": the library, opened on the series of the episode
   /// playing (season selected, episode highlighted), else where it was.
   void _changeVideo() {
-    final coord = SessionState.instance.coordinator;
+    final coord = _graph.coordinator;
     coord.markInput();
     final ref = coord.currentRef.peek();
     final pick = ref == null ? null : pickForRef(_jellyfin, ref);
@@ -401,10 +388,10 @@ class AppShellState extends State<AppShell> with SingleTickerProviderStateMixin
     _selectTab(ShellTab.library);
   }
 
-  /// Library → "Put it up for everyone"; the player opens full. Offline
-  /// it starts a solo session first (just you, on this computer).
+  /// Library → "Put it up for everyone" (alone: Play); the player opens
+  /// full. Before your server is up (starting) it waits for it.
   Future<String?> _putUp(PickedMedia media) async {
-    final session = SessionState.instance;
+    final coord = _graph.coordinator;
     if (media is JellyfinMedia) {
       try {
         putUpJellyfinMedia(_jellyfin, media);
@@ -414,47 +401,28 @@ class AppShellState extends State<AppShell> with SingleTickerProviderStateMixin
       unawaited(_jellyfin.rememberPick(media));
     }
     if (!_online.peek()) {
-      final error = await _startSolo();
-      if (error != null || !mounted) return error;
+      if (!await _graph.navigation.goHome()) return "couldn't start your server";
+      if (!mounted) return null;
     }
     // Alone, a link plays direct: there is nobody to pass it on to.
-    if (media is LinkMedia && session.solo.peek()) {
+    if (media is LinkMedia && coord.alone.peek()) {
       media = LinkMedia(media.url, relay: LinkRelay.direct, anyway: media.anyway);
     }
-    final error = await session.coordinator.swapPicked(media);
+    final error = await coord.swapPicked(media);
     if (error != null || !mounted) return error;
-    final f = session.lastForm;
+    final f = _graph.forms.form;
     f
       ..linkUrl = media is LinkMedia ? media.url : f.linkUrl
       ..mediaPath = media is FileMedia ? media.path : f.mediaPath;
-    unawaited(session.saveForm().catchError((Object _) {}));
+    unawaited(_graph.forms.save().catchError((Object _) {}));
     _autoFull = true;
     _show(PlayerMode.full);
     return null;
   }
 
-  /// Starts a solo session; returns an error text, or null.
-  Future<String?> _startSolo() async {
-    final profile = Profile.instance;
-    try {
-      await profile.ensureLoaded();
-      final name = profile.name.peek().trim();
-      await SessionState.instance.startSolo(ConnectParams(
-        host: '127.0.0.1',
-        port: 0,
-        secret: '',
-        name: name.isEmpty ? 'Me' : name,
-        avatar: profile.avatarBase64(),
-      ));
-      return null;
-    } catch (e) {
-      return "couldn't start playing: $e";
-    }
-  }
-
-  /// Library's "Watch solo": somewhere to pick from (Jellyfin when linked,
-  /// else Files).
-  void _watchSolo() => _openLibrary(_jellyfin.isEmpty ? MediaKind.file : MediaKind.jellyfin);
+  /// The welcome band's "Watch on your own": somewhere to pick from
+  /// (Jellyfin when linked, else Files).
+  void _watchAlone() => _openLibrary(_jellyfin.isEmpty ? MediaKind.file : MediaKind.jellyfin);
 
   // --------------------------------------------------------------- handoff
 
@@ -464,7 +432,7 @@ class AppShellState extends State<AppShell> with SingleTickerProviderStateMixin
   /// Ctrl+V outside a text field (a focused field pastes on its own).
   bool _onKey(KeyEvent e) {
     // Any key is activity (auto sit-out).
-    SessionState.instance.coordinator.markInput();
+    _graph.coordinator.markInput();
     if (e is! KeyDownEvent || e.logicalKey != LogicalKeyboardKey.keyV) return false;
     final keys = HardwareKeyboard.instance;
     if (!(keys.isControlPressed || keys.isMetaPressed) || keys.isShiftPressed || keys.isAltPressed) return false;
@@ -479,7 +447,7 @@ class AppShellState extends State<AppShell> with SingleTickerProviderStateMixin
   /// Clipboard files first, then text (a link or absolute paths). A pasted
   /// image has no taker yet, so the clipboard's image data is not read.
   Future<void> _paste() async {
-    final clip = await SessionState.instance.ports.shell.readPaste();
+    final clip = await _graph.ports.shell.readPaste();
     await _handOff(classifyHandoff(paths: clip.files, text: clip.text), _pointer);
   }
 
@@ -493,7 +461,7 @@ class AppShellState extends State<AppShell> with SingleTickerProviderStateMixin
     final HandoffAction? action;
     try {
       action = await showPopover<HandoffAction>(context,
-          at: align, child: HandoffCard(item: item, solo: _alone.peek(), queue: _online.peek()));
+          at: align, child: HandoffCard(item: item, alone: _alone.peek(), queue: _online.peek()));
     } finally {
       _handoffOpen = false;
     }
@@ -502,7 +470,7 @@ class AppShellState extends State<AppShell> with SingleTickerProviderStateMixin
       case (HandoffVideos(:final paths), HandoffAction.putUp):
         final error = await _putUp(FileMedia(paths.first));
         if (error != null) {
-          SessionState.instance.coordinator.notify(ActionFailed(error));
+          _graph.coordinator.notify(ActionFailed(error));
         } else {
           await FolderStore.instance.ensureLoaded();
           FolderStore.instance.addRecent(paths.first);
@@ -511,15 +479,15 @@ class AppShellState extends State<AppShell> with SingleTickerProviderStateMixin
         // In order: with Play next, the last one added goes first.
         final next = action == HandoffAction.playNext;
         for (final p in next ? paths.reversed : paths) {
-          final error = await SessionState.instance.coordinator.queue.add(FileMedia(p), next: next);
+          final error = await _graph.coordinator.queue.add(FileMedia(p), next: next);
           if (error != null) {
-            SessionState.instance.coordinator.notify(ActionFailed(error));
+            _graph.coordinator.notify(ActionFailed(error));
             break;
           }
         }
       case (HandoffLink(:final url), HandoffAction.queue || HandoffAction.playNext):
         // In the Link page's mode, probed and refused like there.
-        final coord = SessionState.instance.coordinator;
+        final coord = _graph.coordinator;
         final error = await coord.queue
             .add(LinkMedia(url, relay: _picker.linkRelay), next: action == HandoffAction.playNext);
         if (error != null) coord.notify(ActionFailed(error));
@@ -553,7 +521,7 @@ class AppShellState extends State<AppShell> with SingleTickerProviderStateMixin
   }
 
   // Off on Settings: its own drop targets (cookies) take the files there.
-  Widget _dropTarget(Widget child) => SessionState.instance.ports.shell.dropTarget(
+  Widget _dropTarget(Widget child) => _graph.ports.shell.dropTarget(
         enable: _tab != ShellTab.settings,
         onEnter: () => setState(() => _dragging = _onTop),
         onExit: () => setState(() => _dragging = false),
@@ -581,18 +549,19 @@ class AppShellState extends State<AppShell> with SingleTickerProviderStateMixin
 
   // --------------------------------------------------------------- dialogs
 
-  /// Leave asks first; a solo session just stops.
+  /// A friend's server: Leave asks first, then you are back on yours.
+  /// Yours has nothing to leave: the player closes ([_closePlayer]).
   Future<void> _confirmLeave() async {
-    final session = SessionState.instance;
-    if (session.solo.peek()) {
-      await session.leave();
+    final nav = _graph.navigation;
+    if (nav.place.peek() != Place.friend) {
+      _closePlayer();
       return;
     }
     final ok = await showDialog<bool>(
       context: context,
       builder: (context) => AlertDialog(
         title: const Text('Leave server?'),
-        content: const Text('You can rejoin right away.'),
+        content: const Text('You go back to your own server. You can rejoin right away.'),
         actions: [
           TextButton(onPressed: () => Navigator.pop(context, false), child: const Text('Cancel')),
           TextButton(
@@ -603,7 +572,7 @@ class AppShellState extends State<AppShell> with SingleTickerProviderStateMixin
         ],
       ),
     );
-    if (ok == true) await SessionState.instance.leave();
+    if (ok == true) await nav.leaveFriend();
   }
 
   Future<void> _alert(String title, String text) async {
@@ -623,15 +592,16 @@ class AppShellState extends State<AppShell> with SingleTickerProviderStateMixin
     }
   }
 
-  void _connect(ConnectMode mode) => showConnectCard(
+  void _joinFriend() => showJoinCard(
         context,
-        mode: mode,
         flow: _flow,
         join: _join,
-        host: _host,
         healthGet: widget.healthGet,
+        updates: widget.updates,
       );
 
+  void _invite() => unawaited(inviteFriends(context));
+
   // ----------------------------------------------------------------- build
 
   @override
@@ -658,10 +628,9 @@ class AppShellState extends State<AppShell> with SingleTickerProviderStateMixin
                   chatOpen: _chatOpen,
                   unread: _unread,
                   onChat: _toggleChat,
-                  onJoin: () => _connect(ConnectMode.join),
-                  onHost: () => _connect(ConnectMode.host),
+                  onJoin: _joinFriend,
                   onLeave: _confirmLeave,
-                  onInvite: () => _connect(ConnectMode.host),
+                  onInvite: _invite,
                   onProfile: () => showProfileCard(context, onOpenSettings: _openSettings, updates: widget.updates),
                   onShowPlayer: hasMedia && _mode == PlayerMode.none ? () => _show(PlayerMode.mini) : null,
                   windowControls: widget.windowControls,
@@ -694,7 +663,7 @@ class AppShellState extends State<AppShell> with SingleTickerProviderStateMixin
       ),
     );
     // Any pointer use anywhere is activity (auto sit-out).
-    final coord = SessionState.instance.coordinator;
+    final coord = _graph.coordinator;
     return Listener(
       onPointerHover: (e) {
         _pointer = e.localPosition;
@@ -709,41 +678,41 @@ class AppShellState extends State<AppShell> with SingleTickerProviderStateMixin
     );
   }
 
-  /// No Jellyfin account, no server joined or hosted yet, band not
+  /// No Jellyfin account, no friend's server joined yet, band not
   /// dismissed: the welcome band explains the three ways in.
   bool get _newcomer =>
-      !AppSettings.instance.welcomeDismissed.value &&
-      _jellyfin.isEmpty &&
-      SessionState.instance.recents.value.isEmpty;
+      !AppSettings.instance.welcomeDismissed.value && _jellyfin.isEmpty && _graph.forms.recents.value.isEmpty;
 
   Widget _body(bool online, bool alone) {
-    final coord = SessionState.instance.coordinator;
+    final coord = _graph.coordinator;
+    final friend = _graph.navigation.place.value == Place.friend;
     final tabBody = switch (_tab) {
       ShellTab.library => LibraryTab(
           key: ValueKey('library-$_libraryGen'),
           controller: _picker,
           accounts: _jellyfin,
-          solo: alone,
-          // Offline, a put-up starts a solo session, which hosts.
-          isHost: !online || coord.hostFile != null,
-          // Only for newcomers: the strip has Join and Host for everyone else.
-          banner: online || !_newcomer
+          alone: alone,
+          // Your server serves your files itself; a friend's relays them.
+          isHost: !friend,
+          // Only for newcomers alone at home: the strip has Join and Invite
+          // for everyone else.
+          banner: !alone || friend || !_newcomer
               ? null
               : WelcomeBand(
-                  onJoin: () => _connect(ConnectMode.join),
-                  onHost: () => _connect(ConnectMode.host),
-                  onSolo: _watchSolo,
+                  onJoin: _joinFriend,
+                  onInvite: _invite,
+                  onWatch: _watchAlone,
                   onDismiss: () => setState(AppSettings.instance.dismissWelcome),
                 ),
           jellyfinStart: _libraryStart,
           onPutUp: _putUp,
-          // Up next needs a server (a solo session has one).
+          // Up next needs a server (yours, once it is up).
           onAddToQueue: online ? coord.queue.add : null,
           onOpenIntegrations: () => _openSettings(SettingsSection.integrations),
           probe: widget.linkProbe,
         ),
       ShellTab.schedule => SchedulePage(
-          solo: alone,
+          alone: alone,
           onPutUp: _putUp,
           onAddToQueue: online ? coord.queue.add : null,
           onToast: (text) => coord.notify(ScheduleResult(text)),

apps/desktop/lib/src/shell/avatar.dart

@@ -8,7 +8,7 @@ import '../session/identity.dart';
 import '../session/delivery.dart';
 import '../session/party.dart';
 import '../session/session_coordinator.dart';
-import '../state/session_state.dart';
+import '../app/app_graph.dart';
 import 'motion.dart';
 
 /// What an avatar shows: who, their picture or initial on [color], and
@@ -144,8 +144,7 @@ AvatarInfo memberAvatarInfo(MemberView m, StateBroadcast? r, SessionCoordinator
 }
 
 /// Everyone in the server, from the latest state.
-List<AvatarInfo> partyAvatars([SessionCoordinator? coord]) {
-  final c = coord ?? SessionState.instance.coordinator;
+List<AvatarInfo> partyAvatars(SessionCoordinator c) {
   final r = c.serverState.value;
   return [for (final m in r?.members ?? const <MemberView>[]) memberAvatarInfo(m, r, c)];
 }
@@ -158,7 +157,7 @@ class PartyWatch extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) => ListenableBuilder(
-        listenable: SessionState.instance.coordinator.avatars,
+        listenable: AppScope.of(context).coordinator.avatars,
         builder: (context, _) => SignalBuilder(builder: (context) => builder(context)),
       );
 }
@@ -380,8 +379,7 @@ class Pill extends StatelessWidget {
 /// Someone in a feed line or toast: by member [id] when it has one, else
 /// by display [name]; from the latest state when still there, else their
 /// initial on a stable colour.
-AvatarInfo avatarForName(String name, [SessionCoordinator? coord, String id = '']) {
-  final c = coord ?? SessionState.instance.coordinator;
+AvatarInfo avatarForName(String name, SessionCoordinator c, [String id = '']) {
   final r = c.serverState.value;
   final members = r?.members ?? const <MemberView>[];
   // By id when the line has one (names change and repeat), else by name.

apps/desktop/lib/src/shell/chat_panel.dart

@@ -2,7 +2,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:sync_relay_core/core.dart';
 
-import '../state/session_state.dart';
+import '../app/app_graph.dart';
 import '../widgets/app_menu.dart';
 import '../widgets/copy_open.dart';
 import '../widgets/text_focus.dart';
@@ -55,7 +55,7 @@ class _ChatPanelState extends State<ChatPanel> {
   }
 
   void _send() {
-    SessionState.instance.coordinator.sendChat(widget.chat.text);
+    AppScope.of(context).coordinator.sendChat(widget.chat.text);
     widget.chat.clear();
     widget.chatFocus.requestFocus();
   }
@@ -105,7 +105,7 @@ class _ChatPanelState extends State<ChatPanel> {
             child: ValueListenableBuilder<bool>(
               valueListenable: showActivity,
               builder: (context, activity, _) => PartyWatch(builder: (context) {
-                final all = SessionState.instance.coordinator.feedLog.value;
+                final all = AppScope.of(context).coordinator.feedLog.value;
                 final log = activity ? all : [for (final f in all) if (f.action == 'chat') f];
                 if (log.isEmpty) {
                   return Center(
@@ -169,7 +169,7 @@ class ActivityRow extends StatelessWidget {
           anchors: state.contextMenuAnchors,
           buttonItems: [
             ...state.contextMenuButtonItems,
-            for (final (label, action) in _messageActions(item.reason, link))
+            for (final (label, action) in _messageActions(context, item.reason, link))
               ContextMenuButtonItem(
                 label: label,
                 onPressed: () {
@@ -188,7 +188,7 @@ class ActivityRow extends StatelessWidget {
             child: Row(
               crossAxisAlignment: CrossAxisAlignment.start,
               children: [
-                StatusAvatar(info: avatarForName(item.actor, null, item.actorId), size: 34, badges: false),
+                StatusAvatar(info: avatarForName(item.actor, AppScope.of(context).coordinator, item.actorId), size: 34, badges: false),
                 const SizedBox(width: 10),
                 Expanded(
                   child: Column(
@@ -238,17 +238,17 @@ String? firstLinkIn(String text) => RegExp(r'https?://[^\s<>"]+', caseSensitive:
 
 /// What a chat message offers: Copy message, and its link's Copy link and
 /// Open in browser.
-List<(String, VoidCallback)> _messageActions(String text, String? link) => [
-      (ReuseText.copyMessage, () => copyToClipboard(text, done: 'Message copied')),
+List<(String, VoidCallback)> _messageActions(BuildContext context, String text, String? link) => [
+      (ReuseText.copyMessage, () => copyToClipboard(context, text, done: 'Message copied')),
       if (link != null) ...[
-        (ReuseText.copyLink, () => copyToClipboard(link, done: 'Link copied')),
-        (ReuseText.openInBrowser, () => openLink(link)),
+        (ReuseText.copyLink, () => copyToClipboard(context, link, done: 'Link copied')),
+        (ReuseText.openInBrowser, () => openLink(context, link)),
       ],
     ];
 
 /// Right-click beside a chat message: [_messageActions] in the app's menu.
 Future<void> _messageMenu(BuildContext context, String text, String? link) async {
-  final actions = _messageActions(text, link);
+  final actions = _messageActions(context, text, link);
   final pick = await showAppMenu<int>(context, items: [
     for (final (i, (label, _)) in actions.indexed) AppMenuItem(value: i, label: label),
   ]);

apps/desktop/lib/src/shell/connect_cards.dart

@@ -2,12 +2,15 @@ import 'dart:async';
 
 import 'package:flutter/material.dart';
 import 'package:signals/signals_flutter.dart';
-import 'package:sync_relay_core/core.dart' show RelayConstants;
 
+import '../app/app_graph.dart';
 import '../screens/home/connect_flow.dart';
 import '../screens/home/connect_status.dart';
 import '../screens/home/health_probe.dart';
-import '../state/session_state.dart';
+import '../session/invite.dart' show addressIn;
+import '../session/navigation.dart' show Place;
+import '../state/connect_prefs.dart';
+import '../update/update_controller.dart';
 import 'motion.dart';
 
 /// Join card text, owned by the shell so it survives the card closing.
@@ -27,60 +30,45 @@ class JoinFields {
   }
 }
 
-/// Host card text, owned by the shell so it survives the card closing.
-class HostFields {
-  HostFields(ConnectForm f)
-      : port = TextEditingController(text: f.hostPort),
-        secret = TextEditingController(text: f.hostSecret);
-  final TextEditingController port;
-  final TextEditingController secret;
-
-  void dispose() {
-    port.dispose();
-    secret.dispose();
-  }
-}
-
-/// The strip's Join / Host buttons (and solo's Invite friends, the Host
-/// card): a card over the window. It closes itself once the attempt got
-/// in; a failed one shows its error inside.
-Future<void> showConnectCard(
+/// The strip's Join a friend: a card over the window. It closes itself
+/// once the join got in; a failed one shows its error inside.
+Future<void> showJoinCard(
   BuildContext context, {
-  required ConnectMode mode,
   required ConnectFlow flow,
   required JoinFields join,
-  required HostFields host,
   HealthGetter healthGet = defaultHealthGet,
+  UpdateController? updates,
 }) =>
     showPopover<void>(
       context,
       dim: true,
       at: const Alignment(0.8, -0.75),
-      child: _CloseWhenOnline(
-        child: mode == ConnectMode.host
-            ? HostCard(flow: flow, fields: host)
-            : JoinCard(flow: flow, fields: join, healthGet: healthGet),
+      child: _CloseInFriends(
+        child: JoinCard(flow: flow, fields: join, healthGet: healthGet, updates: updates),
       ),
     );
 
-class _CloseWhenOnline extends StatefulWidget {
+class _CloseInFriends extends StatefulWidget {
   final Widget child;
-  const _CloseWhenOnline({required this.child});
+  const _CloseInFriends({required this.child});
 
   @override
-  State<_CloseWhenOnline> createState() => _CloseWhenOnlineState();
+  State<_CloseInFriends> createState() => _CloseInFriendsState();
 }
 
-class _CloseWhenOnlineState extends State<_CloseWhenOnline> {
+class _CloseInFriendsState extends State<_CloseInFriends> {
   late final void Function() _stop;
 
   @override
   void initState() {
     super.initState();
+    final navigation = AppScope.of(context).navigation;
+    var was = navigation.place.peek();
     _stop = effect(() {
-      final s = SessionState.instance;
-      // Solo is in a session too: wait until it is a hosted server.
-      if (s.route.value != AppRoute.session || s.solo.value || s.switching.value) return;
+      final place = navigation.place.value;
+      final arrived = place == Place.friend && was != Place.friend;
+      was = place;
+      if (!arrived) return;
       WidgetsBinding.instance.addPostFrameCallback((_) {
         if (mounted) Navigator.of(context).maybePop();
       });
@@ -97,7 +85,7 @@ class _CloseWhenOnlineState extends State<_CloseWhenOnline> {
   Widget build(BuildContext context) => widget.child;
 }
 
-/// Card frame shared by Join and Host.
+/// The card frame.
 class _Card extends StatelessWidget {
   final String title;
   final List<Widget> children;
@@ -128,14 +116,15 @@ class _Card extends StatelessWidget {
 const _dense = InputDecoration(isDense: true);
 
 /// Recent servers as one-click rows (with live status), then address and
-/// password.
+/// password. Pasting an invite into the address fills the port too.
 class JoinCard extends StatelessWidget {
   final ConnectFlow flow;
   final JoinFields fields;
   final HealthGetter healthGet;
-  const JoinCard({super.key, required this.flow, required this.fields, this.healthGet = defaultHealthGet});
+  final UpdateController? updates;
+  const JoinCard({super.key, required this.flow, required this.fields, this.healthGet = defaultHealthGet, this.updates});
 
-  void _join() => flow.submit(ConnectMode.join, (f) {
+  void _join() => flow.submit((f) {
         f
           ..host = fields.host.text
           ..port = fields.port.text.trim()
@@ -149,20 +138,27 @@ class JoinCard extends StatelessWidget {
     _join();
   }
 
+  /// An invite or "host:port" pasted into the address: split it.
+  void _onAddress(String v) {
+    flow.clearError();
+    final a = addressIn(v);
+    if (a == null || v.trim() == a.host) return;
+    fields.host.text = a.host;
+    fields.port.text = a.port;
+  }
+
   @override
   Widget build(BuildContext context) {
+    final forms = AppScope.of(context).forms;
     return ListenableBuilder(
       listenable: flow,
       builder: (context, _) {
-        final busy = flow.busy == ConnectMode.join;
+        final busy = flow.busy;
         return _Card(
           title: 'Join a friend',
           children: [
             SignalBuilder(builder: (context) {
-              final list = [
-                for (final r in SessionState.instance.recents.value)
-                  if (!r.hosted) r
-              ];
+              final list = forms.recents.value;
               if (list.isEmpty) return const SizedBox.shrink();
               return Column(
                 crossAxisAlignment: CrossAxisAlignment.stretch,
@@ -170,10 +166,10 @@ class JoinCard extends StatelessWidget {
                   const Text('Recent', style: TextStyle(color: Colors.grey)),
                   RecentServerRows(
                     servers: list,
-                    enabled: flow.busy == null,
+                    enabled: !busy,
                     healthGet: healthGet,
                     onJoin: _joinRecent,
-                    onForget: SessionState.instance.forgetServer,
+                    onForget: forms.forget,
                   ),
                   const Divider(),
                 ],
@@ -192,8 +188,8 @@ class JoinCard extends StatelessWidget {
                           key: const ValueKey('join-address'),
                           controller: fields.host,
                           autofocus: true,
-                          decoration: _dense.copyWith(labelText: 'Address', hintText: 'IP or hostname'),
-                          onChanged: (_) => flow.clearError(ConnectMode.join),
+                          decoration: _dense.copyWith(labelText: 'Address', hintText: 'IP, hostname or invite'),
+                          onChanged: _onAddress,
                           onSubmitted: (_) => _join(),
                         ),
                       ),
@@ -222,12 +218,13 @@ class JoinCard extends StatelessWidget {
               ),
             ),
             const SizedBox(height: 16),
-            ConnectButton(flow: flow, mode: ConnectMode.join, label: 'Join', onSubmit: _join, expand: true),
-            ConnectFeedback(flow: flow, mode: ConnectMode.join),
+            ConnectButton(flow: flow, label: 'Join', onSubmit: _join, expand: true),
+            ConnectFeedback(flow: flow, updates: updates),
             const Padding(
               padding: EdgeInsets.only(top: 8),
               child: Text(
-                'Your friend gives you the address and password. No account or Jellyfin needed.',
+                'Your friend gives you their invite (the address) and the password, if any. '
+                'No account or Jellyfin needed. Your own server stays as it is.',
                 style: TextStyle(color: Colors.grey, fontSize: 12),
               ),
             ),
@@ -238,122 +235,6 @@ class JoinCard extends StatelessWidget {
   }
 }
 
-/// Port and password; what to watch is picked afterwards, in the library.
-class HostCard extends StatelessWidget {
-  final ConnectFlow flow;
-  final HostFields fields;
-  const HostCard({super.key, required this.flow, required this.fields});
-
-  void _host() => flow.submit(
-        ConnectMode.host,
-        (f) => f
-          ..hostPort = fields.port.text.trim()
-          ..hostSecret = fields.secret.text,
-      );
-
-  @override
-  Widget build(BuildContext context) {
-    // From a solo session this is "Invite friends": same server settings,
-    // and what plays carries over.
-    final solo = SessionState.instance.solo.peek();
-    return ListenableBuilder(
-      listenable: flow,
-      builder: (context, _) => _Card(
-        title: solo ? 'Invite friends' : 'Host a server',
-        children: [
-          AbsorbPointer(
-            absorbing: flow.busy == ConnectMode.host,
-            child: Column(
-              crossAxisAlignment: CrossAxisAlignment.stretch,
-              children: [
-                TextField(
-                  key: const ValueKey('host-port'),
-                  controller: fields.port,
-                  autofocus: true,
-                  decoration: _dense.copyWith(labelText: 'Port', hintText: '8080'),
-                  keyboardType: TextInputType.number,
-                  onChanged: (_) => flow.clearError(ConnectMode.host),
-                  onSubmitted: (_) => _host(),
-                ),
-                const SizedBox(height: 8),
-                ListenableBuilder(
-                  listenable: fields.secret,
-                  builder: (context, _) => TextField(
-                    key: const ValueKey('host-password'),
-                    controller: fields.secret,
-                    obscureText: true,
-                    decoration: _dense.copyWith(
-                      labelText: 'Password (optional)',
-                      helperText: fields.secret.text.isEmpty ? 'No password — anyone can join' : null,
-                    ),
-                    onSubmitted: (_) => _host(),
-                  ),
-                ),
-                _HostedRecents(fields: fields, enabled: flow.busy == null),
-              ],
-            ),
-          ),
-          const SizedBox(height: 16),
-          ConnectButton(
-              flow: flow, mode: ConnectMode.host, label: solo ? 'Start hosting' : 'Host', onSubmit: _host, expand: true),
-          ConnectFeedback(flow: flow, mode: ConnectMode.host),
-          Padding(
-            padding: const EdgeInsets.only(top: 8),
-            child: Text(
-              solo
-                  ? 'Your video keeps playing from where it is; friends join with your address.'
-                  : 'You pick what to watch afterwards, in the library.',
-              style: const TextStyle(color: Colors.grey, fontSize: 12),
-            ),
-          ),
-        ],
-      ),
-    );
-  }
-}
-
-/// Ports hosted before: one click refills port and password.
-class _HostedRecents extends StatelessWidget {
-  final HostFields fields;
-  final bool enabled;
-  const _HostedRecents({required this.fields, required this.enabled});
-
-  @override
-  Widget build(BuildContext context) {
-    return SignalBuilder(builder: (context) {
-      final list = [
-        for (final r in SessionState.instance.recents.value)
-          if (r.hosted) r
-      ];
-      if (list.isEmpty) return const SizedBox.shrink();
-      return Padding(
-        padding: const EdgeInsets.only(top: 12),
-        child: Wrap(
-          spacing: 8,
-          runSpacing: 8,
-          children: [
-            for (final r in list)
-              InputChip(
-                key: ValueKey('recent-${r.key}'),
-                avatar: Icon(r.secret.isEmpty ? Icons.history : Icons.lock_outline, size: 16),
-                label: Text('Port ${r.port}'),
-                tooltip: 'Use port ${r.port} again',
-                isEnabled: enabled,
-                shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(8)),
-                onPressed: () {
-                  fields.port.text = r.port;
-                  fields.secret.text = r.secret;
-                },
-                deleteButtonTooltipMessage: 'Forget',
-                onDeleted: () => SessionState.instance.forgetServer(r),
-              ),
-          ],
-        ),
-      );
-    });
-  }
-}
-
 /// Recent servers as rows; polls each one's `/health` every
 /// [healthPollEvery] while mounted (i.e. while the Join card is open).
 class RecentServerRows extends StatefulWidget {
@@ -476,8 +357,7 @@ class _RecentRow extends StatelessWidget {
           Text(status, key: const ValueKey('recent-status'), style: TextStyle(color: statusColor)),
           if (h != null && h.needsUpdate)
             Tooltip(
-              message: 'Server protocol ${h.proto}, this app '
-                  '${RelayConstants.protoVersion} — update so both match',
+              message: versionGateText(h),
               child: Container(
                 padding: const EdgeInsets.symmetric(horizontal: 6, vertical: 1),
                 decoration: BoxDecoration(color: scheme.errorContainer, borderRadius: BorderRadius.circular(6)),

apps/desktop/lib/src/shell/handoff.dart

@@ -99,7 +99,7 @@ Handoff classifyHandoff({
 
 /// What the card's buttons ask the shell to do.
 enum HandoffAction {
-  /// Put the (first) video up (offline: watch it solo).
+  /// Put the (first) video up.
   putUp,
   /// Add the video's folder (or the folder) to Files and open it.
   addFolder,
@@ -115,11 +115,11 @@ enum HandoffAction {
 /// pops the [HandoffAction] chosen.
 class HandoffCard extends StatelessWidget {
   final Handoff item;
-  /// Nobody else watches (offline or solo): videos play, no relay talk.
-  final bool solo;
+  /// Nobody else is in the server: videos play, no relay talk.
+  final bool alone;
   /// In a server: videos and links can go to Up next.
   final bool queue;
-  const HandoffCard({super.key, required this.item, required this.solo, this.queue = false});
+  const HandoffCard({super.key, required this.item, required this.alone, this.queue = false});
 
   @override
   Widget build(BuildContext context) {
@@ -144,7 +144,7 @@ class HandoffCard extends StatelessWidget {
           baseName(paths.first),
           paths.length > 1 ? 'and ${paths.length - 1} more · the first one goes up' : 'A video on this computer',
           [
-            button(HandoffAction.putUp, Icons.play_arrow, solo ? 'Play' : 'Put it up', primary: true),
+            button(HandoffAction.putUp, Icons.play_arrow, alone ? 'Play' : 'Put it up', primary: true),
             ...queueButtons,
             button(HandoffAction.addFolder, Icons.create_new_folder_outlined, 'Add its folder to Files'),
           ],
@@ -158,9 +158,9 @@ class HandoffCard extends StatelessWidget {
       HandoffLink(:final url) => (
           Icons.link,
           url,
-          solo ? 'Opens it on the Link page' : 'Pick how the others get it on the Link page',
+          alone ? 'Opens it on the Link page' : 'Pick how the others get it on the Link page',
           [
-            button(HandoffAction.openLink, Icons.link, solo ? 'Open in Link' : 'Put it up as a link…',
+            button(HandoffAction.openLink, Icons.link, alone ? 'Open in Link' : 'Put it up as a link…',
                 primary: true),
             ...queueButtons,
           ],

apps/desktop/lib/src/shell/library_link.dart

@@ -10,7 +10,7 @@ import '../screens/home/media_picker.dart';
 import '../widgets/app_menu.dart';
 import '../widgets/copy_open.dart';
 import '../state/connect_prefs.dart';
-import '../state/session_state.dart';
+import '../app/app_graph.dart';
 import 'motion.dart';
 
 // The Library's Link source: a big paste field, a preview of what the link
@@ -239,7 +239,6 @@ class LinkPreviewStore {
 /// What a link is (see [LinkResolver.probe]).
 typedef LinkProber = Future<LinkProbe> Function(String url);
 
-Future<LinkProbe> defaultLinkProber(String url) => SessionState.instance.ports.links.probe(url);
 
 String _host(Uri uri) => uri.host.startsWith('www.') ? uri.host.substring(4) : uri.host;
 
@@ -254,7 +253,7 @@ String clockText(double seconds) {
 /// duration and thumbnail; a media file its file name and host; a link
 /// that does not open, why ([LinkPreview.problem]). Null for text that is
 /// not an http(s) link.
-Future<LinkPreview?> previewLink(String url, {LinkProber probe = defaultLinkProber}) async {
+Future<LinkPreview?> previewLink(String url, {required LinkProber probe}) async {
   final uri = Uri.tryParse(url.trim());
   if (uri == null || !(uri.scheme == 'http' || uri.scheme == 'https') || uri.host.isEmpty) return null;
   final host = _host(uri);
@@ -290,7 +289,7 @@ Future<LinkPreview?> previewLink(String url, {LinkProber probe = defaultLinkProb
 /// [url]'s preview at once when it was kept before ([LinkPreviewStore]),
 /// else probed and kept (the Up next popover's paste; the Link page has
 /// its own refresh rules).
-Future<LinkPreview?> cachedLinkPreview(String url, {RecentLinks? recents, LinkProber probe = defaultLinkProber}) async {
+Future<LinkPreview?> cachedLinkPreview(String url, {RecentLinks? recents, required LinkProber probe}) async {
   final store = (recents ?? RecentLinks.instance).previews;
   await store.ensureLoaded();
   final kept = store.lookup(url);
@@ -344,27 +343,28 @@ String linkRelayHelp(LinkRelay r) => switch (r) {
     };
 
 /// Under Play when nobody else watches.
-const soloPlayHint = 'Plays just for you. Invite friends any time; it keeps playing.';
+const alonePlayHint = 'Plays just for you. Invite friends any time; it keeps playing.';
 
-/// The Link source. [solo]: nobody else watches (offline or solo), so the
+/// The Link source. [alone]: nobody else is in the server, so the
 /// button says Play and there are no relay modes (the link plays direct).
 class LibraryLinkSource extends StatefulWidget {
   final MediaPickerController controller;
-  final bool solo;
+  final bool alone;
   /// Puts the link up; returns an error text, or null when sent.
   final Future<String?> Function(LinkMedia media) onPutUp;
   /// Adds the link to Up next in the chosen mode; null: no server.
   final AddToQueue? onAddToQueue;
   final RecentLinks recents;
-  final LinkProber probe;
+  /// What a link is; defaults to the app's [LinkResolver.probe].
+  final LinkProber? probe;
   const LibraryLinkSource({
     super.key,
     required this.controller,
     required this.onPutUp,
     this.onAddToQueue,
     required this.recents,
-    this.solo = false,
-    this.probe = defaultLinkProber,
+    this.alone = false,
+    this.probe,
   });
 
   @override
@@ -372,6 +372,8 @@ class LibraryLinkSource extends StatefulWidget {
 }
 
 class _LibraryLinkSourceState extends State<LibraryLinkSource> {
+  LinkProber get _probe => widget.probe ?? AppScope.of(context).ports.links.probe;
+
   MediaPickerController get _c => widget.controller;
   final _previews = <String, LinkPreview?>{};
   String _previewUrl = '';
@@ -450,7 +452,7 @@ class _LibraryLinkSourceState extends State<LibraryLinkSource> {
       if (DateTime.now().difference(known.at) > linkPreviewFreshFor) unawaited(_refresh(url));
       return;
     }
-    final p = await previewLink(url, probe: widget.probe);
+    final p = await previewLink(url, probe: _probe);
     _previews[url] = p;
     _keep(url, p);
     if (mounted) setState(() {});
@@ -459,7 +461,7 @@ class _LibraryLinkSourceState extends State<LibraryLinkSource> {
   /// Probes [url] again behind what is shown; a site out of reach keeps
   /// what was found before. Returns the preview shown afterwards.
   Future<LinkPreview?> _refresh(String url) async {
-    final p = await previewLink(url, probe: widget.probe);
+    final p = await previewLink(url, probe: _probe);
     if (p == null || p.problem == unreachableText) return _previews[url];
     _previews[url] = p;
     _keep(url, p);
@@ -491,12 +493,12 @@ class _LibraryLinkSourceState extends State<LibraryLinkSource> {
     });
     // What the probe found refuses it here, with "Put it up anyway": the
     // server or a friend (with cookies) may still open it.
-    final problem = anyway ? null : (_previews[url] ?? await previewLink(url, probe: widget.probe))?.problem;
+    final problem = anyway ? null : (_previews[url] ?? await previewLink(url, probe: _probe))?.problem;
     String? error = problem;
     if (problem == null) {
       try {
         error = await widget.onPutUp(
-            LinkMedia(url, relay: widget.solo ? LinkRelay.direct : _c.linkRelay, anyway: anyway));
+            LinkMedia(url, relay: widget.alone ? LinkRelay.direct : _c.linkRelay, anyway: anyway));
       } catch (e) {
         error = '$e';
       }
@@ -510,7 +512,7 @@ class _LibraryLinkSourceState extends State<LibraryLinkSource> {
     if (error == null) {
       var p = _previews[url];
       if (p == null) {
-        p = _previews[url] = await previewLink(url, probe: widget.probe);
+        p = _previews[url] = await previewLink(url, probe: _probe);
         _keep(url, p);
       }
       unawaited(widget.recents.add(RecentLink(
@@ -542,7 +544,7 @@ class _LibraryLinkSourceState extends State<LibraryLinkSource> {
     });
     String? error;
     try {
-      error = await add(LinkMedia(link, relay: widget.solo ? LinkRelay.direct : _c.linkRelay), next: next);
+      error = await add(LinkMedia(link, relay: widget.alone ? LinkRelay.direct : _c.linkRelay), next: next);
     } catch (e) {
       error = '$e';
     }
@@ -556,7 +558,7 @@ class _LibraryLinkSourceState extends State<LibraryLinkSource> {
   /// Right-click on a recent link: put it up or queue it, copy or open it.
   Future<void> _recentMenu(BuildContext context, RecentLink l) async {
     final pick = await showAppMenu<String>(context, items: [
-      AppMenuItem(value: 'up', label: widget.solo ? 'Play' : 'Put it up'),
+      AppMenuItem(value: 'up', label: widget.alone ? 'Play' : 'Put it up'),
       if (widget.onAddToQueue != null) ...const [
         AppMenuItem(value: 'queue', label: 'Add to queue'),
         AppMenuItem(value: 'next', label: 'Play next'),
@@ -565,14 +567,14 @@ class _LibraryLinkSourceState extends State<LibraryLinkSource> {
       const AppMenuItem(value: 'title', label: ReuseText.copyTitle),
       const AppMenuItem(value: 'open', label: ReuseText.openInBrowser),
     ]);
-    if (pick == null || !mounted) return;
+    if (pick == null || !mounted || !context.mounted) return;
     switch (pick) {
       case 'copy':
-        return copyToClipboard(l.url, done: 'Link copied');
+        return copyToClipboard(context, l.url, done: 'Link copied');
       case 'title':
-        return copyToClipboard(l.title, done: 'Title copied');
+        return copyToClipboard(context, l.title, done: 'Title copied');
       case 'open':
-        return openLink(l.url);
+        return openLink(context, l.url);
     }
     _c.link.text = l.url;
     switch (pick) {
@@ -592,11 +594,11 @@ class _LibraryLinkSourceState extends State<LibraryLinkSource> {
     ]);
     switch (pick) {
       case 'copy':
-        await copyToClipboard(url, done: 'Link copied');
+        if (context.mounted) await copyToClipboard(context, url, done: 'Link copied');
       case 'title':
-        await copyToClipboard(p!.title, done: 'Title copied');
+        if (context.mounted) await copyToClipboard(context, p!.title, done: 'Title copied');
       case 'open':
-        await openLink(url);
+        if (context.mounted) await openLink(context, url);
     }
   }
 
@@ -614,7 +616,7 @@ class _LibraryLinkSourceState extends State<LibraryLinkSource> {
   Widget build(BuildContext context) {
     final scheme = Theme.of(context).colorScheme;
     final t = Theme.of(context).textTheme;
-    final solo = widget.solo;
+    final alone = widget.alone;
     final url = _c.link.text.trim();
     final preview = url.isEmpty ? null : _previews[url];
     final loading = url.isNotEmpty && !_previews.containsKey(url);
@@ -638,7 +640,7 @@ class _LibraryLinkSourceState extends State<LibraryLinkSource> {
       icon: _busy
           ? const SizedBox.square(dimension: 16, child: CircularProgressIndicator(strokeWidth: 2))
           : const Icon(Icons.play_arrow),
-      label: Text(solo ? 'Play' : 'Put it up'),
+      label: Text(alone ? 'Play' : 'Put it up'),
       style: FilledButton.styleFrom(
         minimumSize: const Size(0, 56),
         shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(16)),
@@ -705,10 +707,10 @@ class _LibraryLinkSourceState extends State<LibraryLinkSource> {
                         if (queue != null) ...[const SizedBox(width: 8), queue],
                       ]),
               ),
-              if (solo || _error != null) ...[
+              if (alone || _error != null) ...[
                 const SizedBox(height: 8),
                 Text(
-                  _error ?? soloPlayHint,
+                  _error ?? alonePlayHint,
                   key: const ValueKey('link-hint'),
                   textAlign: TextAlign.center,
                   style: t.bodySmall?.copyWith(color: _error != null ? scheme.error : Colors.grey),
@@ -718,7 +720,7 @@ class _LibraryLinkSourceState extends State<LibraryLinkSource> {
                     child: TextButton(
                       key: const ValueKey('link-put-up-anyway'),
                       onPressed: _busy ? null : () => _go(anyway: true),
-                      child: Text(solo ? 'Play it anyway' : 'Put it up anyway'),
+                      child: Text(alone ? 'Play it anyway' : 'Put it up anyway'),
                     ),
                   ),
               ],
@@ -737,7 +739,7 @@ class _LibraryLinkSourceState extends State<LibraryLinkSource> {
                         ),
                       ),
               ),
-              if (!solo) ...[
+              if (!alone) ...[
                 const SizedBox(height: 28),
                 Text('How the others get it', style: t.titleSmall),
                 const SizedBox(height: 10),

apps/desktop/lib/src/shell/library_tab.dart

@@ -14,7 +14,7 @@ import '../jellyfin/picker_source.dart';
 import '../jellyfin/session_media.dart';
 import '../screens/home/media_picker.dart';
 import '../session/app_events.dart' show ActionFailed;
-import '../state/session_state.dart';
+import '../app/app_graph.dart';
 import 'library_link.dart';
 import 'motion.dart';
 import 'welcome.dart';
@@ -68,12 +68,11 @@ const detailsDockFrom = 1000.0;
 /// Jellyfin cards select on click and open their details in a panel at
 /// the right (docked from [detailsDockFrom], floating over the library
 /// below it); a double-click or the panel's button puts it up. With
-/// nobody else watching ([solo]: offline or a solo session) the buttons
-/// say Play and putting something up starts (or uses) a solo session.
+/// nobody else in the server ([alone], D9) the buttons say Play.
 class LibraryTab extends StatefulWidget {
   final MediaPickerController controller;
   final JellyfinAccounts accounts;
-  final bool solo;
+  final bool alone;
   /// This app hosts the server: its files stream from here directly.
   final bool isHost;
   final BrowseStart? jellyfinStart;
@@ -85,9 +84,10 @@ class LibraryTab extends StatefulWidget {
   final VoidCallback? onOpenIntegrations;
   /// Defaults to [RecentLinks.instance].
   final RecentLinks? recentLinks;
-  final LinkProber probe;
+  /// What a link is; defaults to the app's.
+  final LinkProber? probe;
   /// The Files source (tests inject one); defaults to [FilesPage].
-  final Widget Function(BuildContext context, {required bool solo, required bool relayed,
+  final Widget Function(BuildContext context, {required bool alone, required bool relayed,
       required Future<String?> Function(String path) onPlay, String? nowPlayingPath})? filesBuilder;
   /// Clock for the Jellyfin Continue row (tests pin it).
   final DateTime Function() now;
@@ -97,7 +97,7 @@ class LibraryTab extends StatefulWidget {
     super.key,
     required this.controller,
     required this.accounts,
-    required this.solo,
+    required this.alone,
     required this.isHost,
     required this.onPutUp,
     this.onAddToQueue,
@@ -105,7 +105,7 @@ class LibraryTab extends StatefulWidget {
     this.jellyfinStart,
     this.onOpenIntegrations,
     this.recentLinks,
-    this.probe = defaultLinkProber,
+    this.probe,
     this.filesBuilder,
     this.now = DateTime.now,
     this.banner,
@@ -200,14 +200,14 @@ class _LibraryTabState extends State<LibraryTab> {
   /// A card's menu: errors as a toast (the Notifier's).
   Future<void> _cardQueue(JellyfinSelection sel, {bool next = false}) async {
     final error = await _queueJellyfin(sel, next: next);
-    if (error != null) SessionState.instance.notifier.notify(ActionFailed(error));
+    if (error != null && mounted) AppScope.of(context).notifier.notify(ActionFailed(error));
   }
 
   /// Double-click on a card: put it up, errors as a toast.
   Future<void> _doublePutUp(JellyfinSelection sel) async {
     _c.select(sel);
     final error = await _putUpJellyfin(sel);
-    if (error != null) SessionState.instance.notifier.notify(ActionFailed(error));
+    if (error != null && mounted) AppScope.of(context).notifier.notify(ActionFailed(error));
   }
 
   // -------------------------------------------------------------- build
@@ -271,7 +271,7 @@ class _LibraryTabState extends State<LibraryTab> {
         ),
       MediaKind.link => LibraryLinkSource(
           controller: _c,
-          solo: widget.solo,
+          alone: widget.alone,
           recents: widget.recentLinks ?? RecentLinks.instance,
           probe: widget.probe,
           onPutUp: _put,
@@ -305,7 +305,7 @@ class _LibraryTabState extends State<LibraryTab> {
             child: JellyfinDetailsPanel(
               controller: _browse,
               selection: shown,
-              solo: widget.solo,
+              alone: widget.alone,
               onPutUp: _putUpJellyfin,
               onAddToQueue: widget.onAddToQueue == null ? null : _queueJellyfin,
               onClose: () => _c.select(null),
@@ -366,17 +366,17 @@ class _LibraryTabState extends State<LibraryTab> {
     final relayed = !widget.isHost;
     Future<String?> play(String path) => _put(FileMedia(path));
     return SignalBuilder(builder: (context) {
-      final session = SessionState.instance;
-      final now = session.route.value == AppRoute.session
-          ? nowPlayingFile(session.coordinator.serverState.value?.media, session.lastForm.mediaPath)
+      final graph = AppScope.of(context);
+      final now = graph.navigation.online.value
+          ? nowPlayingFile(graph.coordinator.serverState.value?.media, graph.forms.form.mediaPath)
           : null;
       final b = widget.filesBuilder;
       if (b != null) {
-        return b(context, solo: widget.solo, relayed: relayed, onPlay: play, nowPlayingPath: now);
+        return b(context, alone: widget.alone, relayed: relayed, onPlay: play, nowPlayingPath: now);
       }
       final add = widget.onAddToQueue;
       return FilesPage(
-          solo: widget.solo,
+          alone: widget.alone,
           relayed: relayed,
           onPlay: play,
           onAddToQueue: add == null ? null : (path, {next = false}) => add(FileMedia(path), next: next),

apps/desktop/lib/src/shell/mark_problem.dart

@@ -3,7 +3,7 @@ import 'package:flutter/services.dart';
 import 'package:sync_relay_core/core.dart' show RelayConstants;
 
 import '../session/app_events.dart' show ProblemMarked;
-import '../state/session_state.dart';
+import '../app/app_graph.dart';
 import '../widgets/app_menu.dart' show AppGlass;
 import 'motion.dart';
 
@@ -17,8 +17,8 @@ const markProblemKey = SingleActivator(LogicalKeyboardKey.keyB, control: true, s
 /// Asks for the note, then marks; the toast says where it went.
 Future<void> showMarkProblem(BuildContext context) async {
   final note = await showPopover<String>(context, at: Alignment.center, child: const MarkProblemCard());
-  if (note == null) return;
-  final coord = SessionState.instance.coordinator;
+  if (note == null || !context.mounted) return;
+  final coord = AppScope.of(context).coordinator;
   final inSession = await coord.markProblem(note);
   coord.notify(ProblemMarked(inSession: inSession));
 }

apps/desktop/lib/src/shell/now_playing_title.dart

@@ -3,7 +3,7 @@ import 'package:flutter/material.dart';
 import 'package:signals/signals_flutter.dart';
 
 import '../session/now_playing.dart';
-import '../state/session_state.dart';
+import '../app/app_graph.dart';
 import '../widgets/app_menu.dart';
 import '../widgets/copy_open.dart';
 import 'motion.dart';
@@ -15,22 +15,22 @@ Uint8List? Function(String hash)? debugArtBytes;
 /// The one lookup for media art (cover, banner) by content hash: null
 /// when there is none or it has not arrived yet (listeners of
 /// [artChanges] hear when it lands).
-Uint8List? artBytes(String hash) {
+Uint8List? artBytes(BuildContext context, String hash) {
   if (hash.isEmpty) return null;
   final debug = debugArtBytes;
   if (debug != null) return debug(hash);
-  return SessionState.instance.coordinator.art.bytesFor(hash);
+  return AppScope.of(context).coordinator.art.bytesFor(hash);
 }
 
 /// Notifies when art arrives.
-Listenable artChanges() => SessionState.instance.coordinator.art;
+Listenable artChanges(BuildContext context) => AppScope.of(context).coordinator.art;
 
 final _images = <String, MemoryImage>{};
 
 /// [hash]'s art as an image, the same provider while the bytes are the
 /// same (so a rebuild never decodes again).
-ImageProvider? artImage(String hash) {
-  final bytes = artBytes(hash);
+ImageProvider? artImage(BuildContext context, String hash) {
+  final bytes = artBytes(context, hash);
   if (bytes == null) return null;
   final hit = _images[hash];
   if (hit != null && identical(hit.bytes, bytes)) return hit;
@@ -59,7 +59,7 @@ class ArtCover extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final image = artImage(hash);
+    final image = artImage(context, hash);
     final r = BorderRadius.circular(width >= 80 ? 10 : 6);
     return Container(
       width: wide ? width * 1.5 * 16 / 9 : width,
@@ -166,10 +166,10 @@ class NowPlayingTitle extends StatelessWidget {
   Widget build(BuildContext context) => GestureDetector(
         onSecondaryTap: () => nowPlayingMenu(context),
         child: ListenableBuilder(
-          listenable: artChanges(),
+          listenable: artChanges(context),
           builder: (context, _) => SignalBuilder(
             builder: (context) => NowPlayingBlock(
-              now: SessionState.instance.coordinator.nowPlaying.value,
+              now: AppScope.of(context).coordinator.nowPlaying.value,
               cover: cover,
               compact: compact,
             ),
@@ -182,7 +182,7 @@ class NowPlayingTitle extends StatelessWidget {
 /// Copy link and Open in browser; a Jellyfin item on a server linked here,
 /// Open in Jellyfin. [context]: where the menu opens.
 Future<void> nowPlayingMenu(BuildContext context) async {
-  final coord = SessionState.instance.coordinator;
+  final coord = AppScope.of(context).coordinator;
   final now = coord.nowPlaying.peek();
   if (now == null) return;
   final link = coord.currentLink();
@@ -200,12 +200,12 @@ Future<void> nowPlayingMenu(BuildContext context) async {
   ]);
   switch (pick) {
     case 'title':
-      await copyToClipboard(title, done: 'Title copied');
+      if (context.mounted) await copyToClipboard(context, title, done: 'Title copied');
     case 'link':
-      await copyToClipboard(link!, done: 'Link copied');
+      if (context.mounted) await copyToClipboard(context, link!, done: 'Link copied');
     case 'open':
-      await openLink(link!);
+      if (context.mounted) await openLink(context, link!);
     case 'jellyfin':
-      await openLink(page!);
+      if (context.mounted) await openLink(context, page!);
   }
 }

apps/desktop/lib/src/shell/party_strip.dart

@@ -1,5 +1,3 @@
-import 'dart:io';
-
 import 'package:flutter/material.dart';
 import 'package:signals/signals_flutter.dart';
 import 'package:sync_relay_core/core.dart';
@@ -7,7 +5,10 @@ import 'package:sync_relay_core/core.dart';
 import '../screens/home/ui.dart' show appName, displayVersion, shortVersion;
 import '../session/delivery.dart';
 import '../session/party.dart';
-import '../state/session_state.dart';
+import '../app/app_graph.dart';
+import '../session/app_events.dart' show ActionFailed;
+import '../session/invite.dart';
+import '../session/navigation.dart' show Place;
 import '../widgets/app_keys.dart';
 import '../widgets/app_menu.dart';
 import '../widgets/copy_open.dart';
@@ -36,9 +37,11 @@ const stripAvatarSize = 42.0;
 const stripCompactBelow = 1100.0;
 
 /// The 60 px strip over everything: your avatar (profile), the tabs, and
-/// the party: offline Join a friend / Host, solo a "Solo" chip, Invite
-/// friends and Stop, online the avatars (members card), server and
-/// readiness, chat and Leave. Empty space drags the window.
+/// the party. Alone on your own server it is a plain player's: Join a
+/// friend and Invite (a "Sharing" chip while your server is open to
+/// friends); with others there the avatars (members card), server and
+/// readiness, chat, and Invite (yours) or Leave (a friend's). Empty space
+/// drags the window.
 class PartyStrip extends StatelessWidget {
   final ShellTab tab;
   final ValueChanged<ShellTab> onTab;
@@ -46,11 +49,11 @@ class PartyStrip extends StatelessWidget {
   final int unread;
   final VoidCallback onChat;
   final VoidCallback onJoin;
-  final VoidCallback onHost;
   final VoidCallback onLeave;
   final VoidCallback onProfile;
-  /// Solo: host from here, keeping what plays.
-  final VoidCallback? onInvite;
+  /// Opens your server to friends (if it is not yet) and copies the
+  /// invite.
+  final VoidCallback onInvite;
 
   /// Online with something up but the player closed: brings it back.
   final VoidCallback? onShowPlayer;
@@ -65,10 +68,9 @@ class PartyStrip extends StatelessWidget {
     required this.unread,
     required this.onChat,
     required this.onJoin,
-    required this.onHost,
     required this.onLeave,
     required this.onProfile,
-    this.onInvite,
+    required this.onInvite,
     this.onShowPlayer,
     this.windowControls = true,
   });
@@ -79,11 +81,18 @@ class PartyStrip extends StatelessWidget {
     final compact = MediaQuery.sizeOf(context).width < stripCompactBelow;
     final row = SignalBuilder(
       builder: (context) {
-        final session = SessionState.instance;
-        final coord = session.coordinator;
-        final online = session.route.value == AppRoute.session;
-        final solo = online && (session.solo.value || session.switching.value);
-        final self = online ? coord.selfMember.value : null;
+        final graph = AppScope.of(context);
+        final coord = graph.coordinator;
+        final nav = graph.navigation;
+        final online = nav.online.value;
+        final home = nav.home.value;
+        final friend = nav.place.value == Place.friend;
+        // Others there (or a friend's server): the party; else a plain
+        // player (D9).
+        final social = friend || (online && !coord.alone.value);
+        final shared = graph.yourServer.shared.value;
+        final canInvite = graph.yourServer.port.value != null && !graph.yourServer.busy.value;
+        final self = social ? coord.selfMember.value : null;
         return Row(
           children: [
             const SizedBox(width: 16),
@@ -97,11 +106,11 @@ class PartyStrip extends StatelessWidget {
                 child: StatusAvatar(
                   info: selfAvatarInfo(
                     ready: self?.ready ?? false,
-                    host: online && !solo && coord.hostFile != null,
+                    host: social && home,
                     error: online ? coord.playerError.value : '',
                   ),
                   size: stripAvatarSize,
-                  ring: online,
+                  ring: social,
                 ),
               ),
             ),
@@ -140,29 +149,7 @@ class PartyStrip extends StatelessWidget {
                 onPressed: onShowPlayer,
                 icon: const Icon(Icons.smart_display_outlined, size: 20),
               ),
-            if (solo) ...[
-              _SoloChip(compact: compact, busy: session.switching.value),
-              const SizedBox(width: 10),
-              if (compact)
-                FilledButton(
-                  key: const ValueKey('strip-invite'),
-                  onPressed: session.switching.value ? null : onInvite,
-                  child: const Text('Invite'),
-                )
-              else
-                FilledButton.icon(
-                  key: const ValueKey('strip-invite'),
-                  onPressed: session.switching.value ? null : onInvite,
-                  icon: const Icon(Icons.group_add_outlined, size: 18),
-                  label: const Text('Invite friends'),
-                ),
-              const SizedBox(width: 8),
-              OutlinedButton(
-                key: const ValueKey('strip-leave'),
-                onPressed: session.switching.value ? null : onLeave,
-                child: const Text('Stop'),
-              ),
-            ] else if (online) ...[
+            if (social) ...[
               PartyWatch(
                 builder: (context) => AvatarStack(
                   key: const ValueKey('party-avatars'),
@@ -196,41 +183,30 @@ class PartyStrip extends StatelessWidget {
                 ),
               ),
               const SizedBox(width: 4),
-              OutlinedButton(
-                key: const ValueKey('strip-leave'),
-                onPressed: onLeave,
-                child: const Text('Leave'),
-              ),
+              if (friend)
+                OutlinedButton(
+                  key: const ValueKey('strip-leave'),
+                  onPressed: onLeave,
+                  child: const Text('Leave'),
+                )
+              else
+                _InviteButton(compact: compact, onInvite: canInvite ? onInvite : null),
             ] else ...[
-              if (!compact) ...[
-                Container(
-                  width: 7,
-                  height: 7,
-                  decoration: BoxDecoration(color: scheme.outline, shape: BoxShape.circle),
-                ),
-                const SizedBox(width: 6),
-                Text('Offline', style: TextStyle(color: scheme.onSurfaceVariant)),
-                const SizedBox(width: 12),
-              ],
-              if (compact) ...[
-                FilledButton(key: const ValueKey('strip-join'), onPressed: onJoin, child: const Text('Join')),
+              if (shared != null) ...[
+                _SharingChip(compact: compact, port: shared.port),
                 const SizedBox(width: 8),
-                FilledButton.tonal(key: const ValueKey('strip-host'), onPressed: onHost, child: const Text('Host')),
-              ] else ...[
-                FilledButton.icon(
+              ],
+              if (compact)
+                FilledButton.tonal(key: const ValueKey('strip-join'), onPressed: onJoin, child: const Text('Join'))
+              else
+                FilledButton.tonalIcon(
                   key: const ValueKey('strip-join'),
                   onPressed: onJoin,
                   icon: const Icon(Icons.login_rounded, size: 18),
                   label: const Text('Join a friend'),
                 ),
-                const SizedBox(width: 8),
-                FilledButton.tonalIcon(
-                  key: const ValueKey('strip-host'),
-                  onPressed: onHost,
-                  icon: const Icon(Icons.podcasts_rounded, size: 18),
-                  label: const Text('Host'),
-                ),
-              ],
+              const SizedBox(width: 8),
+              _InviteButton(compact: compact, onInvite: canInvite ? onInvite : null),
             ],
             const SizedBox(width: 8),
             if (windowControls) ...[
@@ -282,14 +258,15 @@ class _ServerLabel extends StatelessWidget {
     builder: (context) {
       // "connecting…", "reconnecting…", "ready 2/3" (the ready counter
       // counts who the presence policy counts), from the one status.
-      final line = SessionState.instance.coordinator.status.value.party;
+      final graph = AppScope.of(context);
+      final line = graph.coordinator.status.value.party;
       return Column(
         key: const ValueKey('server-label'),
         mainAxisSize: MainAxisSize.min,
         crossAxisAlignment: CrossAxisAlignment.start,
         children: [
           Text(
-            serverName(),
+            serverName(graph),
             style: const TextStyle(fontWeight: FontWeight.w600, height: 1.1),
           ),
           Text(
@@ -306,50 +283,74 @@ class _ServerLabel extends StatelessWidget {
   );
 }
 
-/// "Solo" alone, "Your server" when hosting, else the joined server's
-/// name (its `--name`), or its address while unknown.
-String serverName() {
-  final session = SessionState.instance;
-  if (session.solo.value) return 'Solo';
-  if (session.coordinator.hostFile != null) return 'Your server';
-  final label = session.serverLabel.value;
-  return label.isNotEmpty ? label : session.lastForm.host;
+/// "Your server" at home, else the joined server's name (its `--name`),
+/// or its address while unknown.
+String serverName(AppGraph graph) {
+  final nav = graph.navigation;
+  if (nav.home.value) return 'Your server';
+  final label = nav.serverLabel.value;
+  return label.isNotEmpty ? label : nav.address.value;
 }
 
-/// Solo: just you, on your own; a spinner while it becomes a server.
-class _SoloChip extends StatelessWidget {
+/// Invite: opens your server to friends (if it is not yet) and copies
+/// the invite.
+class _InviteButton extends StatelessWidget {
   final bool compact;
-  final bool busy;
-  const _SoloChip({required this.compact, required this.busy});
+  final VoidCallback? onInvite;
+  const _InviteButton({required this.compact, required this.onInvite});
+
+  @override
+  Widget build(BuildContext context) {
+    const tip = 'Copy an invite friends can join with (opens your server to them)';
+    if (compact) {
+      return Tooltip(
+        message: tip,
+        child: FilledButton(key: const ValueKey('strip-invite'), onPressed: onInvite, child: const Text('Invite')),
+      );
+    }
+    return Tooltip(
+      message: tip,
+      child: FilledButton.icon(
+        key: const ValueKey('strip-invite'),
+        onPressed: onInvite,
+        icon: const Icon(Icons.group_add_outlined, size: 18),
+        label: const Text('Invite'),
+      ),
+    );
+  }
+}
+
+/// Your server is open to friends and nobody came yet: the port; a click
+/// opens the members card (the invite, Stop sharing).
+class _SharingChip extends StatelessWidget {
+  final bool compact;
+  final int port;
+  const _SharingChip({required this.compact, required this.port});
 
   @override
   Widget build(BuildContext context) {
     final scheme = Theme.of(context).colorScheme;
     return Tooltip(
-      message: busy
-          ? 'Starting your server…'
-          : 'Watching on your own. Nobody can join until you invite friends.',
-      child: Container(
-        key: const ValueKey('solo-chip'),
-        padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 6),
-        decoration: BoxDecoration(
-          color: scheme.surfaceContainerHigh,
-          borderRadius: BorderRadius.circular(20),
-        ),
-        child: Row(
-          mainAxisSize: MainAxisSize.min,
-          children: [
-            if (busy)
-              const SizedBox.square(dimension: 14, child: CircularProgressIndicator(strokeWidth: 2))
-            else
-              Icon(Icons.person_outline_rounded, size: 16, color: scheme.primary),
-            const SizedBox(width: 6),
-            Text(busy ? 'Inviting…' : 'Solo', style: const TextStyle(fontWeight: FontWeight.w600)),
-            if (!compact && !busy) ...[
+      message: 'Friends can join with your invite. Click for the invite or to stop sharing.',
+      child: InkWell(
+        key: const ValueKey('sharing-chip'),
+        borderRadius: BorderRadius.circular(20),
+        onTap: () => showMembersCard(context),
+        child: Container(
+          padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 6),
+          decoration: BoxDecoration(color: scheme.surfaceContainerHigh, borderRadius: BorderRadius.circular(20)),
+          child: Row(
+            mainAxisSize: MainAxisSize.min,
+            children: [
+              Icon(Icons.podcasts_rounded, size: 16, color: scheme.primary),
               const SizedBox(width: 6),
-              Text('only you', style: TextStyle(color: scheme.onSurfaceVariant, fontSize: 12)),
+              const Text('Sharing', style: TextStyle(fontWeight: FontWeight.w600)),
+              if (!compact) ...[
+                const SizedBox(width: 6),
+                Text('port $port', style: TextStyle(color: scheme.onSurfaceVariant, fontSize: 12)),
+              ],
             ],
-          ],
+          ),
         ),
       ),
     );
@@ -425,50 +426,16 @@ class StripTab extends StatelessWidget {
 }
 
 /// Who is in the server, from the avatars: status, host / relay pills,
-/// per member force ready, nudge and sit out, and the address to invite
-/// friends.
+/// per member force ready, nudge and sit out, and the invite (yours) or
+/// the address (a friend's).
 Future<void> showMembersCard(BuildContext context) => showPopover<void>(
   context,
   at: const Alignment(0.7, -0.84),
   child: const MembersCard(),
 );
 
-/// "ip:port" for each of [addresses] friends could dial: IPv4, neither
-/// loopback nor link-local, private (LAN) ranges first, no repeats.
-List<String> inviteAddresses(Iterable<InternetAddress> addresses, String port) {
-  bool private(List<int> b) =>
-      b[0] == 10 || (b[0] == 192 && b[1] == 168) || (b[0] == 172 && b[1] >= 16 && b[1] < 32);
-  final usable = [
-    for (final a in addresses)
-      if (a.type == InternetAddressType.IPv4 &&
-          !a.isLoopback &&
-          !a.isLinkLocal &&
-          !(a.rawAddress[0] == 169 && a.rawAddress[1] == 254))
-        a,
-  ];
-  final ordered = [
-    ...usable.where((a) => private(a.rawAddress)),
-    ...usable.where((a) => !private(a.rawAddress)),
-  ];
-  return {for (final a in ordered) '${a.address}:$port'}.toList();
-}
-
-/// This machine's [inviteAddresses] (empty when the interfaces can't be
-/// listed).
-Future<List<String>> lanInviteAddresses(String port) async {
-  try {
-    final interfaces = await NetworkInterface.list(type: InternetAddressType.IPv4);
-    return inviteAddresses([for (final i in interfaces) ...i.addresses], port);
-  } catch (e) {
-    debugPrint('list network interfaces failed: $e');
-    return const [];
-  }
-}
-
 class MembersCard extends StatelessWidget {
-  /// This machine's invite addresses for a port (tests pass fixed ones).
-  final Future<List<String>> Function(String port) lanAddresses;
-  const MembersCard({super.key, this.lanAddresses = lanInviteAddresses});
+  const MembersCard({super.key});
 
   @override
   Widget build(BuildContext context) {
@@ -481,15 +448,14 @@ class MembersCard extends StatelessWidget {
         width: 340,
         child: PartyWatch(
           builder: (context) {
-            final session = SessionState.instance;
-            final coord = session.coordinator;
+            final graph = AppScope.of(context);
+            final coord = graph.coordinator;
+            final nav = graph.navigation;
             final r = coord.serverState.value;
-            final hosting = coord.hostFile != null;
-            final address = hosting
-                ? null
-                : '${session.lastForm.host}:${session.lastForm.port}';
+            final home = nav.home.value;
+            final address = home ? null : nav.address.value;
             final delivery = coord.status.value.delivery;
-            final server = session.serverVersion.value;
+            final server = nav.serverVersion.value;
             return Column(
               mainAxisSize: MainAxisSize.min,
               crossAxisAlignment: CrossAxisAlignment.stretch,
@@ -500,7 +466,7 @@ class MembersCard extends StatelessWidget {
                     crossAxisAlignment: CrossAxisAlignment.start,
                     children: [
                       Text(
-                        ['In the server', ?address].join(' · '),
+                        home ? 'Your server' : ['In the server', ?address].join(' · '),
                         style: const TextStyle(fontWeight: FontWeight.w600),
                       ),
                       if (server.isNotEmpty)
@@ -531,23 +497,20 @@ class MembersCard extends StatelessWidget {
                     ),
                   ),
                 const Divider(),
-                if (address != null)
+                if (home)
+                  const YourInvite()
+                else if (address != null && address.isNotEmpty)
                   Padding(
                     padding: const EdgeInsets.fromLTRB(12, 0, 12, 8),
                     child: Align(
                       alignment: Alignment.centerLeft,
                       child: TextButton.icon(
                         key: const ValueKey('copy-invite'),
-                        onPressed: () => copyToClipboard(address, done: 'Invite address copied'),
+                        onPressed: () => copyToClipboard(context, address, done: 'Invite address copied'),
                         icon: const Icon(Icons.copy, size: 16),
                         label: const Text('Copy invite address'),
                       ),
                     ),
-                  )
-                else
-                  _HostInvite(
-                    port: session.lastForm.hostPort,
-                    lanAddresses: lanAddresses,
                   ),
               ],
             );
@@ -571,7 +534,7 @@ class _MemberTile extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final coord = SessionState.instance.coordinator;
+    final coord = AppScope.of(context).coordinator;
     final m = member;
     final since = m.goneSince;
     final status = m.presence == Presence.gone
@@ -660,76 +623,90 @@ class VersionText extends StatelessWidget {
 bool versionDiffers(String version, {String own = appVersion}) =>
     version.isNotEmpty && own != '0.0.0-dev' && version != '0.0.0-dev' && version != own;
 
-/// Hosting: the addresses friends on this network can join, the first
-/// one behind "Copy invite address", and what friends elsewhere need.
-class _HostInvite extends StatefulWidget {
-  final String port;
-  final Future<List<String>> Function(String port) lanAddresses;
-  const _HostInvite({required this.port, required this.lanAddresses});
-
-  @override
-  State<_HostInvite> createState() => _HostInviteState();
-}
-
-class _HostInviteState extends State<_HostInvite> {
-  late final Future<List<String>> _addresses = widget.lanAddresses(widget.port);
+/// Your server in the members card: shared, the invite's address
+/// (Copy invite), a hint for friends outside the network and Stop
+/// sharing; not shared, Invite (opens it and copies the invite).
+class YourInvite extends StatelessWidget {
+  const YourInvite({super.key});
 
   @override
   Widget build(BuildContext context) {
     final muted = Theme.of(context).colorScheme.onSurfaceVariant;
-    return FutureBuilder<List<String>>(
-      future: _addresses,
-      builder: (context, snap) {
-        final list = snap.data ?? const <String>[];
-        void copy(String a) => copyToClipboard(a, done: 'Invite address copied');
-        return Padding(
-          padding: const EdgeInsets.fromLTRB(12, 0, 12, 12),
-          child: Column(
-            key: const ValueKey('host-invite'),
-            crossAxisAlignment: CrossAxisAlignment.start,
-            children: [
+    final graph = AppScope.of(context);
+    final yours = graph.yourServer;
+    return SignalBuilder(builder: (context) {
+      final invite = yours.shared.value;
+      final busy = yours.busy.value || yours.port.value == null;
+      return Padding(
+        padding: const EdgeInsets.fromLTRB(12, 0, 12, 12),
+        child: Column(
+          key: const ValueKey('your-invite'),
+          crossAxisAlignment: CrossAxisAlignment.start,
+          children: [
+            if (invite == null) ...[
+              Padding(
+                padding: const EdgeInsets.fromLTRB(8, 0, 8, 6),
+                child: Text('Only you can reach it. Invite opens it to friends; nothing you watch stops.',
+                    style: TextStyle(color: muted, fontSize: 12)),
+              ),
               TextButton.icon(
                 key: const ValueKey('copy-invite'),
-                onPressed: list.isEmpty ? null : () => copy(list.first),
-                icon: const Icon(Icons.copy, size: 16),
-                label: const Text('Copy invite address'),
+                onPressed: busy ? null : () => inviteFriends(context),
+                icon: const Icon(Icons.group_add_outlined, size: 16),
+                label: const Text('Invite'),
               ),
-              if (snap.connectionState != ConnectionState.done)
-                const SizedBox.shrink()
-              else if (list.isEmpty)
-                Padding(
-                  padding: const EdgeInsets.symmetric(horizontal: 8),
-                  child: Text('No network address found', style: TextStyle(color: muted)),
-                )
-              else
-                for (final a in list)
-                  InkWell(
-                    key: ValueKey('invite-$a'),
-                    borderRadius: BorderRadius.circular(8),
-                    onTap: () => copy(a),
-                    child: Padding(
-                      padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 4),
-                      child: Row(
-                        children: [
-                          Expanded(child: Text(a, style: const TextStyle(fontFamily: 'monospace'))),
-                          Icon(Icons.copy, size: 14, color: muted),
-                        ],
-                      ),
-                    ),
-                  ),
+            ] else ...[
               Padding(
-                padding: const EdgeInsets.fromLTRB(8, 6, 8, 0),
+                padding: const EdgeInsets.symmetric(horizontal: 8),
+                child: Text(invite.address,
+                    key: const ValueKey('invite-address'), style: const TextStyle(fontFamily: 'monospace')),
+              ),
+              Wrap(
+                spacing: 4,
+                children: [
+                  TextButton.icon(
+                    key: const ValueKey('copy-invite'),
+                    onPressed: () => copyToClipboard(context, invite.text, done: 'Invite copied'),
+                    icon: const Icon(Icons.copy, size: 16),
+                    label: const Text('Copy invite'),
+                  ),
+                  TextButton(
+                    key: const ValueKey('stop-sharing'),
+                    onPressed: busy ? null : () => yours.stopSharing(),
+                    child: const Text('Stop sharing'),
+                  ),
+                ],
+              ),
+              Padding(
+                padding: const EdgeInsets.fromLTRB(8, 2, 8, 0),
                 child: Text(
-                  'Works for friends on your network. Friends elsewhere need port '
-                  '${widget.port} forwarded on your router, or a server they can '
-                  'all reach (like a VPS).',
+                  'Works for friends on your network. Friends elsewhere need port ${invite.port} '
+                  'forwarded on your router, or a server they can all reach (like a VPS). '
+                  'Stop sharing sends everyone else out; you and Up next stay.',
                   style: TextStyle(color: muted, fontSize: 12),
                 ),
               ),
             ],
-          ),
-        );
-      },
-    );
+          ],
+        ),
+      );
+    });
   }
 }
+
+/// Invite: opens your server to friends if it is not yet and copies the
+/// invite ("Invite copied"); a port that can't be opened is a notice.
+Future<void> inviteFriends(BuildContext context) async {
+  final graph = AppScope.of(context);
+  final Invite invite;
+  try {
+    invite = await graph.yourServer.invite();
+  } catch (e) {
+    final port = graph.forms.form.hostPort;
+    graph.notifier.notify(ActionFailed(
+        "couldn't open your server on port $port: $e — pick another port in Settings → Party & network"));
+    return;
+  }
+  if (!context.mounted) return;
+  await copyToClipboard(context, invite.text, done: 'Invite copied · ${invite.address}');
+}

apps/desktop/lib/src/shell/player_status.dart

@@ -3,7 +3,7 @@ import 'dart:async';
 import 'package:flutter/material.dart';
 
 import '../session/session_coordinator.dart';
-import '../state/session_state.dart';
+import '../app/app_graph.dart';
 import '../widgets/app_menu.dart' show AppGlass;
 import 'avatar.dart';
 import 'motion.dart';
@@ -13,8 +13,8 @@ export '../session/status.dart' show StatusAction, StatusKind, StatusLevel, Stat
 /// The pill's line from the session's [SessionCoordinator.status]
 /// (tracked: call inside a builder); "Connecting…" only once it has taken
 /// [PlayerStatus.connectGrace] ([slowConnect]).
-StatusLine? playerStatusNow({bool slowConnect = false}) {
-  final line = SessionState.instance.coordinator.status.value.line;
+StatusLine? playerStatusNow(SessionCoordinator coord, {bool slowConnect = false}) {
+  final line = coord.status.value.line;
   if (line?.kind == StatusKind.connecting && !slowConnect) return null;
   return line;
 }
@@ -73,9 +73,9 @@ class _PlayerStatusState extends State<PlayerStatus> {
   @override
   Widget build(BuildContext context) {
     return PartyWatch(builder: (context) {
-      final coord = SessionState.instance.coordinator;
+      final coord = AppScope.of(context).coordinator;
       _trackConnecting(coord.status.value.line);
-      final view = playerStatusNow(slowConnect: _slow);
+      final view = playerStatusNow(coord, slowConnect: _slow);
       if (view != null) _last = view;
       final shown = _last;
       final ready = view?.action == StatusAction.ready;

apps/desktop/lib/src/shell/profile_card.dart

@@ -10,7 +10,7 @@ import 'package:sync_relay_core/core.dart' show Presence;
 
 import '../jellyfin/accounts.dart';
 import '../session/identity.dart';
-import '../state/session_state.dart';
+import '../app/app_graph.dart';
 import '../update/update_controller.dart';
 import 'avatar.dart';
 import 'motion.dart';
@@ -74,11 +74,12 @@ class _ProfileCardState extends State<ProfileCard> {
       child: SizedBox(
         width: 360,
         child: SignalBuilder(builder: (context) {
-          final session = SessionState.instance;
-          final coord = session.coordinator;
-          final online = session.route.value == AppRoute.session;
+          final graph = AppScope.of(context);
+          final coord = graph.coordinator;
+          // Alone it is a plain player: no ring, no crown.
+          final online = graph.navigation.online.value && !coord.alone.value;
           final self = online ? coord.selfMember.value : null;
-          final hosting = online && !session.solo.value && coord.hostFile != null;
+          final hosting = online && graph.navigation.home.value;
           final color = _p.color.value;
           final png = _p.picture.value;
           final out = self?.presence == Presence.away;
@@ -164,7 +165,7 @@ class _ProfileCardState extends State<ProfileCard> {
                             runSpacing: 4,
                             children: [
                               if (hosting) const Pill('host', Colors.amber),
-                              Pill(online ? 'in a server' : 'offline',
+                              Pill(online ? 'with others' : 'just you',
                                   online ? Colors.greenAccent : Colors.grey),
                               if (online)
                                 Pill(out ? 'sitting out' : (self?.ready ?? false) ? 'ready' : 'not ready',
@@ -231,7 +232,7 @@ class _ProfileCardState extends State<ProfileCard> {
                 child: Text(
                   online
                       ? 'Name and picture update for everyone in the server right away. Colour is yours only.'
-                      : 'Others see your name and picture when you join. Colour is yours only.',
+                      : 'Others see your name and picture when they join you or you join them. Colour is yours only.',
                   style: small,
                 ),
               ),
@@ -331,7 +332,7 @@ class _CropPickerState extends State<CropPicker> {
   Future<void> _pick() async {
     final List<String> files;
     try {
-      files = await SessionState.instance.ports.folders.pickFiles(
+      files = await AppScope.of(context).ports.folders.pickFiles(
         dialogTitle: 'Pick a picture',
         extensions: const ['png', 'jpg', 'jpeg', 'webp', 'gif', 'bmp'],
       );

apps/desktop/lib/src/shell/session_player.dart

@@ -18,7 +18,7 @@ import '../screens/session/player_controls.dart';
 import '../session/app_events.dart' show ShaderMessage;
 import '../session/session_coordinator.dart';
 import '../shaders/shader_presets.dart';
-import '../state/session_state.dart';
+import '../app/app_graph.dart';
 import '../state/settings.dart';
 import '../widgets/app_keys.dart';
 import '../widgets/text_focus.dart';
@@ -122,12 +122,14 @@ class _SessionPlayerState extends State<SessionPlayer> {
     onLeave: () => widget.onLeave(),
   );
 
-  SessionCoordinator get _coord => SessionState.instance.coordinator;
+  late final SessionCoordinator _coord = AppScope.of(context).coordinator;
   bool get _full => widget.mode == PlayerMode.full;
 
   @override
   void initState() {
     super.initState();
+    // The model reads it in dispose too, when the tree is no longer there.
+    _model;
     _coord.jellyfin.ensureLoaded();
     HardwareKeyboard.instance.addHandler(_globalKey);
     // Tab (AppKeys) reaches the chat through here in fullscreen.
@@ -173,8 +175,9 @@ class _SessionPlayerState extends State<SessionPlayer> {
   /// app-wide ([AppKeys]).
   bool _globalKey(KeyEvent event) {
     if (event is! KeyDownEvent || !mounted) return false;
-    if (SessionState.instance.route.peek() != AppRoute.session) return false;
-    // Mini: Esc is the last step out, asking to leave the server.
+    if (!AppScope.of(context).navigation.online.peek()) return false;
+    // Mini: Esc is the last step out (a friend's server: asking to leave
+    // it; yours: the player closes).
     if (!_full) {
       if (event.logicalKey != LogicalKeyboardKey.escape) return false;
       if (ModalRoute.of(context)?.isCurrent == false || textInputFocused()) return false;
@@ -301,7 +304,7 @@ class _SessionPlayerState extends State<SessionPlayer> {
                 if (_full) ...[
                   _blockedCard(),
                   _actionArea(),
-                  if (widget.fullscreen) ...[if (!SessionState.instance.solo.value) _pausedParty(), _unreadChip()],
+                  if (widget.fullscreen) ...[if (!_coord.alone.value) _pausedParty(), _unreadChip()],
                   _volumeReadout(),
                 ] else
                   _miniOverlay(),
@@ -641,7 +644,7 @@ class _SessionPlayerState extends State<SessionPlayer> {
                               style: const TextStyle(color: Colors.white70, fontSize: 12)),
                           const Spacer(),
                           Flexible(
-                            child: Text(playerStatusNow()?.short ?? '',
+                            child: Text(playerStatusNow(_coord)?.short ?? '',
                                 maxLines: 1,
                                 overflow: TextOverflow.ellipsis,
                                 style: const TextStyle(color: Colors.amber, fontSize: 12)),
@@ -786,7 +789,7 @@ class _MiniSeekBar extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final playback = SessionState.instance.coordinator.playback;
+    final playback = AppScope.of(context).coordinator.playback;
     return SignalBuilder(builder: (context) {
       final d = playback.duration.value;
       final p = playback.position.value;

apps/desktop/lib/src/shell/settings_tab.dart

@@ -17,7 +17,7 @@ import '../screens/home/ui.dart' show appName, displayVersion;
 import '../session/auto_sit_out.dart' show AutoSitOutTimes;
 import '../sfx/sfx.dart';
 import '../sfx/sound_bank.dart';
-import '../state/session_state.dart';
+import '../app/app_graph.dart';
 import '../state/settings.dart';
 import '../update/update_controller.dart';
 import '../widgets/app_menu.dart';
@@ -86,7 +86,7 @@ class SettingsTab extends StatelessWidget {
         ];
       case SettingsSection.network:
         return [
-          const HostDefaultsPanel(),
+          const YourServerPanel(),
           const RecentServersPanel(),
           SettingsPanel(
             title: 'Watching',
@@ -258,16 +258,18 @@ class SettingsTab extends StatelessWidget {
   }
 }
 
-/// Party & network: what the Host card starts with.
-class HostDefaultsPanel extends StatefulWidget {
-  const HostDefaultsPanel({super.key});
+/// Party & network: your server's port and password, used when you
+/// Invite (the next time sharing starts).
+class YourServerPanel extends StatefulWidget {
+  const YourServerPanel({super.key});
 
   @override
-  State<HostDefaultsPanel> createState() => _HostDefaultsPanelState();
+  State<YourServerPanel> createState() => _YourServerPanelState();
 }
 
-class _HostDefaultsPanelState extends State<HostDefaultsPanel> {
-  final _form = SessionState.instance.lastForm;
+class _YourServerPanelState extends State<YourServerPanel> {
+  late final _forms = AppScope.of(context).forms;
+  late final _form = _forms.form;
   late final _port = TextEditingController(text: _form.hostPort);
   late final _secret = TextEditingController(text: _form.hostSecret);
   bool _show = false;
@@ -286,22 +288,22 @@ class _HostDefaultsPanelState extends State<HostDefaultsPanel> {
 
   Future<void> _save() async {
     try {
-      await SessionState.instance.saveForm();
+      await _forms.save();
     } catch (e) {
-      debugPrint('save host defaults failed: $e');
+      debugPrint('save your server settings failed: $e');
     }
   }
 
   @override
   Widget build(BuildContext context) {
     return SettingsPanel(
-      title: 'Hosting',
+      title: 'Your server',
       child: Column(
         crossAxisAlignment: CrossAxisAlignment.stretch,
         children: [
           SettingRow(
-            label: 'Default port',
-            help: 'Where your server listens when you host; friends dial it',
+            label: 'Port',
+            help: 'Where friends reach your server once you Invite (the next time you start sharing)',
             control: SizedBox(
               width: 120,
               child: TextField(
@@ -320,7 +322,8 @@ class _HostDefaultsPanelState extends State<HostDefaultsPanel> {
           ),
           SettingRow(
             label: 'Password',
-            help: 'Asked of everyone joining your server; blank lets in anyone who reaches the port',
+            help: 'Asked of every friend joining your server; blank lets in anyone who reaches the port '
+                '(the next time you start sharing)',
             control: SizedBox(
               width: 220,
               child: TextField(
@@ -355,16 +358,16 @@ class RecentServersPanel extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final session = SessionState.instance;
+    final forms = AppScope.of(context).forms;
     final muted = Theme.of(context).colorScheme.onSurfaceVariant;
     return SettingsPanel(
       title: 'Recent servers',
       child: SignalBuilder(builder: (context) {
-        final list = session.recents.value;
+        final list = forms.recents.value;
         return Column(
           crossAxisAlignment: CrossAxisAlignment.stretch,
           children: [
-            Text('Join and Host offer these in one click; remove the ones you no longer use',
+            Text('Join offers these in one click; remove the ones you no longer use',
                 style: TextStyle(color: muted, fontSize: 12)),
             if (list.isEmpty)
               Padding(
@@ -375,13 +378,13 @@ class RecentServersPanel extends StatelessWidget {
               ListTile(
                 key: ValueKey('recent-${r.key}'),
                 contentPadding: EdgeInsets.zero,
-                leading: Icon(r.hosted ? Icons.cast_outlined : Icons.dns_outlined),
-                title: Text(r.hosted ? 'Hosted on port ${r.port}' : '${r.host}:${r.port}'),
+                leading: const Icon(Icons.dns_outlined),
+                title: Text('${r.host}:${r.port}'),
                 subtitle: r.secret.isEmpty ? null : const Text('password saved'),
                 trailing: IconButton(
                   tooltip: 'Remove',
                   icon: const Icon(Icons.close, size: 18),
-                  onPressed: () => session.forgetServer(r),
+                  onPressed: () => forms.forget(r),
                 ),
               ),
           ],
@@ -403,7 +406,7 @@ class YtDlpSettings extends StatefulWidget {
 }
 
 class _YtDlpSettingsState extends State<YtDlpSettings> {
-  late final Future<YtDlp> _y = widget.ytDlp ?? SessionState.instance.ports.links.ytDlp;
+  late final Future<YtDlp> _y = widget.ytDlp ?? AppScope.of(context).ports.links.ytDlp;
 
   @override
   Widget build(BuildContext context) {
@@ -488,7 +491,7 @@ class _YtDlpCookieSettingsState extends State<YtDlpCookieSettings> {
   Future<void> _pickFile() async {
     final List<String> files;
     try {
-      files = await SessionState.instance.ports.folders.pickFiles(
+      files = await AppScope.of(context).ports.folders.pickFiles(
         dialogTitle: 'Pick a cookies.txt or a JSON cookie export',
         extensions: const ['txt', 'json'],
       );
@@ -548,7 +551,7 @@ class _YtDlpCookieSettingsState extends State<YtDlpCookieSettings> {
   @override
   Widget build(BuildContext context) {
     final scheme = Theme.of(context).colorScheme;
-    return SessionState.instance.ports.shell.dropTarget(
+    return AppScope.of(context).ports.shell.dropTarget(
       onEnter: () => setState(() => _dragging = true),
       onExit: () => setState(() => _dragging = false),
       onDrop: (paths, _) {
@@ -835,7 +838,8 @@ class NotificationsInfo extends StatelessWidget {
 class SoundSettings extends StatelessWidget {
   const SoundSettings({super.key});
 
-  void _preview(SfxKind kind) => unawaited(SessionState.instance.sfx.preview(kind, readyIndex: 2));
+  void _preview(BuildContext context, SfxKind kind) =>
+      unawaited(AppScope.of(context).sfx.preview(kind, readyIndex: 2));
 
   @override
   Widget build(BuildContext context) {
@@ -859,7 +863,7 @@ class SoundSettings extends StatelessWidget {
                   key: const ValueKey('sound-volume'),
                   value: volume,
                   onChanged: s.setSoundVolume,
-                  onChangeEnd: (_) => _preview(SfxKind.ready),
+                  onChangeEnd: (_) => _preview(context, SfxKind.ready),
                 ),
               ),
               SizedBox(width: 44, child: Text('${(volume * 100).round()}%', textAlign: TextAlign.end)),
@@ -876,7 +880,7 @@ class SoundSettings extends StatelessWidget {
                 value: overall,
                 onChanged: (v) {
                   s.setSoundPreset(v);
-                  _preview(SfxKind.ready);
+                  _preview(context, SfxKind.ready);
                 },
                 items: [
                   for (final MapEntry(key: p, value: (name, _)) in presetInfo.entries) (p.name, name),
@@ -894,7 +898,7 @@ class SoundSettings extends StatelessWidget {
                   IconButton(
                     key: ValueKey('sound-play-${kind.name}'),
                     tooltip: 'Play',
-                    onPressed: volume == 0 ? null : () => _preview(kind),
+                    onPressed: volume == 0 ? null : () => _preview(context, kind),
                     icon: const Icon(Icons.play_arrow_rounded),
                   ),
                   const SizedBox(width: 4),
@@ -910,7 +914,7 @@ class SoundSettings extends StatelessWidget {
                     style: muted,
                     onChanged: (v) {
                       s.setSoundPresetFor(kind.name, v);
-                      if (volume > 0) _preview(kind);
+                      if (volume > 0) _preview(context, kind);
                     },
                     items: [
                       (null, 'Same as set'),

apps/desktop/lib/src/shell/sit_out_card.dart

@@ -4,7 +4,7 @@ import 'package:flutter/material.dart';
 import 'package:signals/signals_flutter.dart';
 
 import '../playback/media_marks.dart' show formatClock;
-import '../state/session_state.dart';
+import '../app/app_graph.dart';
 import '../sync/state_diff.dart' show serverPositionAt;
 import 'now_playing_title.dart';
 import 'start_banner.dart';
@@ -41,10 +41,10 @@ class _SitOutCardState extends State<SitOutCard> {
 
   @override
   Widget build(BuildContext context) {
-    final coord = SessionState.instance.coordinator;
+    final coord = AppScope.of(context).coordinator;
     final small = widget.compact;
     return ListenableBuilder(
-      listenable: artChanges(),
+      listenable: artChanges(context),
       builder: (context, _) => SignalBuilder(builder: (context) {
         final r = coord.serverState.value;
         final now = coord.nowPlaying.value;

apps/desktop/lib/src/shell/start_banner.dart

@@ -4,7 +4,7 @@ import 'package:flutter/material.dart';
 import 'package:signals/signals_flutter.dart';
 
 import '../session/now_playing.dart';
-import '../state/session_state.dart';
+import '../app/app_graph.dart';
 import 'motion.dart';
 import 'now_playing_title.dart';
 
@@ -21,8 +21,8 @@ class StartCard extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final banner = artImage(now.bannerHash);
-    final cover = banner == null ? artImage(now.posterHash) : null;
+    final banner = artImage(context, now.bannerHash);
+    final cover = banner == null ? artImage(context, now.posterHash) : null;
     final episode = now.episode;
     return LayoutBuilder(builder: (context, box) {
       final h = box.maxHeight;
@@ -145,10 +145,10 @@ class _StartBannerState extends State<StartBanner> {
 
   @override
   Widget build(BuildContext context) {
-    final coord = SessionState.instance.coordinator;
+    final coord = AppScope.of(context).coordinator;
     return IgnorePointer(
       child: ListenableBuilder(
-        listenable: artChanges(),
+        listenable: artChanges(context),
         builder: (context, _) => SignalBuilder(builder: (context) {
           final r = coord.serverState.value;
           final now = coord.nowPlaying.value;

apps/desktop/lib/src/shell/toasts.dart

@@ -4,7 +4,7 @@ import 'package:flutter/material.dart';
 import 'package:signals/signals_flutter.dart';
 
 import '../session/session_coordinator.dart' show ToastItem;
-import '../state/session_state.dart';
+import '../app/app_graph.dart';
 import 'avatar.dart';
 import 'motion.dart';
 
@@ -73,7 +73,7 @@ class _PartyToastsState extends State<PartyToasts> {
   @override
   void initState() {
     super.initState();
-    final coord = SessionState.instance.coordinator;
+    final coord = AppScope.of(context).coordinator;
     // What was there before this mounted is old news.
     _seen = {for (final t in coord.toasts.peek()) t.id};
     _stop = effect(() {
@@ -127,7 +127,7 @@ class _PartyToastsState extends State<PartyToasts> {
 
   void _open(ShellToast t) {
     widget.onOpenChat?.call();
-    SessionState.instance.notifier.dismiss(t.id);
+    AppScope.of(context).notifier.dismiss(t.id);
   }
 
   @override
@@ -282,7 +282,7 @@ class _Thumb extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final thumbs = SessionState.instance.coordinator.queue.thumbs;
+    final thumbs = AppScope.of(context).coordinator.queue.thumbs;
     return ClipRRect(
       key: const ValueKey('toast-thumb'),
       borderRadius: BorderRadius.circular(6),

apps/desktop/lib/src/shell/welcome.dart

@@ -12,15 +12,16 @@ const appTagline = 'Watch together, in sync';
 /// the app name (else under it).
 const welcomeWideFrom = 980.0;
 
-/// Top of the Library while not in a server: the app's name and the three
-/// ways in, Join a friend first (what most people came for), then Host and
-/// Watch solo. None of them needs Jellyfin.
+/// Top of the Library for newcomers alone on their own server: the app's
+/// name and the three ways in, Join a friend first (what most people came
+/// for), then Invite friends and Watch on your own. None of them needs
+/// Jellyfin.
 class WelcomeBand extends StatelessWidget {
   final VoidCallback onJoin;
-  final VoidCallback onHost;
-  final VoidCallback onSolo;
+  final VoidCallback onInvite;
+  final VoidCallback onWatch;
   final VoidCallback? onDismiss;
-  const WelcomeBand({super.key, required this.onJoin, required this.onHost, required this.onSolo, this.onDismiss});
+  const WelcomeBand({super.key, required this.onJoin, required this.onInvite, required this.onWatch, this.onDismiss});
 
   @override
   Widget build(BuildContext context) {
@@ -63,23 +64,23 @@ class WelcomeBand extends StatelessWidget {
         key: const ValueKey('way-join'),
         icon: Icons.login_rounded,
         title: 'Join a friend',
-        caption: 'Got an address from a friend? Join with it. Nothing to set up.',
+        caption: 'Got an invite from a friend? Join with it. Nothing to set up.',
         primary: true,
         onTap: onJoin,
       ),
       WayCard(
-        key: const ValueKey('way-host'),
-        icon: Icons.podcasts_rounded,
-        title: 'Host',
-        caption: 'You have the video. Friends join you and watch it with you.',
-        onTap: onHost,
+        key: const ValueKey('way-invite'),
+        icon: Icons.group_add_outlined,
+        title: 'Invite friends',
+        caption: 'You have the video. Copy an invite; friends join you and watch it with you.',
+        onTap: onInvite,
       ),
       WayCard(
-        key: const ValueKey('way-solo'),
+        key: const ValueKey('way-watch'),
         icon: Icons.person_outline_rounded,
-        title: 'Watch solo',
+        title: 'Watch on your own',
         caption: 'Just you: play anything below. Invite friends any time.',
-        onTap: onSolo,
+        onTap: onWatch,
       ),
     ];
     Widget row(List<Widget> cards) => IntrinsicHeight(

apps/desktop/lib/src/state/connect_prefs.dart

@@ -1,4 +1,8 @@
+import 'dart:convert';
+
+import 'package:flutter/foundation.dart' show debugPrint;
 import 'package:hive_ce/hive.dart';
+import 'package:signals/signals.dart';
 
 const connectFormBoxName = 'connect_form';
 
@@ -19,3 +23,165 @@ String readString(Box box, String key, String fallback) {
   final v = box.get(key);
   return v is String ? v : fallback;
 }
+
+const connectKeyHostPort = 'hostPort';
+const connectKeyHostSecret = 'hostSecret';
+const connectKeyRecents = 'recents';
+const maxRecentServers = 6;
+
+/// The connect form: the Join card's address ([host]/[port]/[secret]),
+/// your server's port and password when shared ([hostPort]/[hostSecret]),
+/// the profile name and the last media picked.
+class ConnectForm {
+  String host;
+  String port;
+  String secret;
+  String hostPort;
+  String hostSecret;
+  String name;
+  String avatarPath;
+  String mediaPath;
+  String linkUrl;
+  ConnectForm({
+    this.host = '127.0.0.1',
+    this.port = '8080',
+    this.secret = '',
+    this.hostPort = '8080',
+    this.hostSecret = '',
+    this.name = '',
+    this.avatarPath = '',
+    this.mediaPath = '',
+    this.linkUrl = '',
+  });
+
+  ConnectForm copy() => ConnectForm(
+        host: host,
+        port: port,
+        secret: secret,
+        hostPort: hostPort,
+        hostSecret: hostSecret,
+        name: name,
+        avatarPath: avatarPath,
+        mediaPath: mediaPath,
+        linkUrl: linkUrl,
+      );
+}
+
+/// A friend's server the user got into, shown as a Recent row on the
+/// Join card (one click joins).
+class RecentServer {
+  final String host;
+  final String port;
+  final String secret;
+  const RecentServer({required this.host, required this.port, this.secret = ''});
+
+  String get key => '${host.toLowerCase()}:$port';
+
+  Map<String, Object> toJson() => {'host': host, 'port': port, 'secret': secret};
+
+  /// Null for anything unreadable and for the hosted entries older
+  /// versions kept (your server has no recents).
+  static RecentServer? fromJson(Object? j) {
+    if (j is! Map || j['hosted'] == true) return null;
+    final host = j['host'], port = j['port'], secret = j['secret'];
+    if (host is! String || port is! String) return null;
+    return RecentServer(host: host, port: port, secret: secret is String ? secret : '');
+  }
+}
+
+/// Newest first, one entry per server, capped at [maxRecentServers].
+List<RecentServer> pushRecent(List<RecentServer> list, RecentServer s) => [
+      s,
+      ...list.where((r) => r.key != s.key),
+    ].take(maxRecentServers).toList();
+
+String encodeRecents(List<RecentServer> list) => jsonEncode([for (final r in list) r.toJson()]);
+
+List<RecentServer> decodeRecents(Object? raw) {
+  if (raw is! String) return const [];
+  try {
+    final list = jsonDecode(raw);
+    if (list is! List) return const [];
+    return [
+      for (final j in list) ?RecentServer.fromJson(j),
+    ].take(maxRecentServers).toList();
+  } catch (_) {
+    return const [];
+  }
+}
+
+/// Before recents existed only the last form was stored: a saved remote
+/// address becomes the first Recent row.
+List<RecentServer> migrateRecents(
+    {required bool hadForm, required String host, required String port, required String secret}) {
+  final h = host.trim().toLowerCase();
+  if (!hadForm || h.isEmpty || h == '127.0.0.1' || h == 'localhost') return const [];
+  return [RecentServer(host: host.trim(), port: port, secret: secret)];
+}
+
+/// The connect form and the recent servers, kept in the `connect_form`
+/// box. Made by the composition root; the Join card, your server (its
+/// port and password), the profile and the library read and write it.
+class ConnectStore {
+  final form = ConnectForm();
+  final recents = signal<List<RecentServer>>(const []);
+
+  Future<void> load() async {
+    final box = await openConnectFormBox();
+    form
+      ..host = readString(box, connectKeyHost, '127.0.0.1')
+      ..port = readString(box, connectKeyPort, '8080')
+      ..secret = readString(box, connectKeySecret, '');
+    // Old installs had one port/password for both modes.
+    form
+      ..hostPort = readString(box, connectKeyHostPort, form.port)
+      ..hostSecret = readString(box, connectKeyHostSecret, form.secret)
+      ..name = readString(box, connectKeyName, '')
+      ..avatarPath = readString(box, connectKeyAvatarPath, '')
+      ..mediaPath = readString(box, connectKeyMediaPath, '')
+      ..linkUrl = readString(box, connectKeyLinkUrl, '');
+    recents.value = box.containsKey(connectKeyRecents)
+        ? decodeRecents(box.get(connectKeyRecents))
+        : migrateRecents(
+            hadForm: box.containsKey(connectKeyHost), host: form.host, port: form.port, secret: form.secret);
+  }
+
+  Future<void> save() async {
+    final box = connectFormBoxIfOpen() ?? await openConnectFormBox();
+    await box.putAll({
+      connectKeyHost: form.host,
+      connectKeyPort: form.port,
+      connectKeySecret: form.secret,
+      connectKeyHostPort: form.hostPort,
+      connectKeyHostSecret: form.hostSecret,
+      connectKeyName: form.name,
+      connectKeyAvatarPath: form.avatarPath,
+      connectKeyMediaPath: form.mediaPath,
+      connectKeyLinkUrl: form.linkUrl,
+      connectKeyRecents: encodeRecents(recents.peek()),
+    });
+  }
+
+  /// [save] whatever happens (a failed join is exactly when the user
+  /// wants the form back); a failure is only logged.
+  Future<void> saveQuietly() async {
+    try {
+      await save();
+    } catch (e, st) {
+      debugPrint('save connect form failed: $e\n$st');
+    }
+  }
+
+  Future<void> remember(RecentServer server) async {
+    recents.value = pushRecent(recents.peek(), server);
+    await saveQuietly();
+  }
+
+  Future<void> forget(RecentServer server) async {
+    recents.value = [
+      for (final r in recents.peek())
+        if (r.key != server.key) r,
+    ];
+    await saveQuietly();
+  }
+}

apps/desktop/lib/src/state/server_isolate.dart

@@ -8,7 +8,8 @@ import 'package:sync_relay_server/server.dart';
 Future<void> _serverMain((Map<String, Object?>, SendPort) args) =>
     serve(args.$1, events: args.$2);
 
-/// The hosted server, running [serve] on its own isolate. Its log lines
+/// This app's own server ("your server"), running [serve] on its own
+/// isolate for the whole app run. Its log lines
 /// go to [onLog]; if the isolate dies without being asked to stop,
 /// [onCrash] gets the cause once.
 class ServerIsolate {
@@ -33,7 +34,7 @@ class ServerIsolate {
 
   /// Spawns the server and waits until it listens. Throws a
   /// [StateError] with the server's message if it cannot start.
-  /// [loopbackOnly]: 127.0.0.1 only (the solo session). [logDir]: where
+  /// [loopbackOnly]: 127.0.0.1 only until [share]. [logDir]: where
   /// the server writes its session log (none when null).
   static Future<ServerIsolate> start(
     AppConfig config, {
@@ -156,6 +157,46 @@ class ServerIsolate {
     }
   }
 
+  /// Opens the server to the network ([SyncServer.share]): a listener on
+  /// every interface at [port], the password [secret], the Jellyfin relay
+  /// login [jellyfin]. Returns the bound port; throws a [StateError] with
+  /// the server's reason (a port in use) when it cannot.
+  Future<int> share({required int port, required String secret, JellyfinCredential? jellyfin,
+      Duration timeout = const Duration(seconds: 10)}) async {
+    if (_exited.isCompleted) throw StateError('the server is not running');
+    final reply = ReceivePort('server share');
+    try {
+      _stop.send({
+        't': 'share',
+        'port': port,
+        'secret': secret,
+        'jellyfin': ?jellyfin?.toMap(),
+        'reply': reply.sendPort,
+      });
+      final msg = await reply.first.timeout(timeout);
+      if (msg is Map && msg['ok'] == true) return msg['port'] as int;
+      throw StateError(msg is Map ? '${msg['message']}' : 'the server did not answer');
+    } on TimeoutException {
+      throw StateError('the server did not answer');
+    } finally {
+      reply.close();
+    }
+  }
+
+  /// Closes the network listener again ([SyncServer.unshare]): everyone
+  /// but this app's own member leaves; nothing else changes.
+  Future<void> unshare({Duration timeout = const Duration(seconds: 5)}) async {
+    if (_exited.isCompleted) return;
+    final reply = ReceivePort('server unshare');
+    try {
+      _stop.send({'t': 'unshare', 'reply': reply.sendPort});
+      await reply.first.timeout(timeout);
+    } catch (_) {
+    } finally {
+      reply.close();
+    }
+  }
+
   /// Asks the server to close its sockets and exit; kills the isolate if it
   /// has not exited within [timeout].
   Future<void> stop({Duration timeout = const Duration(seconds: 3)}) async {

apps/desktop/lib/src/state/session_state.dart

@@ -1,543 +0,0 @@
-import 'dart:async';
-import 'dart:convert';
-import 'dart:math';
-
-import 'package:flutter/widgets.dart';
-import 'package:signals/signals_flutter.dart';
-import 'package:sync_relay_core/core.dart';
-
-import '../jellyfin/accounts.dart';
-import '../jellyfin/session_media.dart';
-import '../screens/home/health_probe.dart';
-import '../screens/home/picked_media.dart';
-import '../platform/app_log.dart' show appLogDir;
-import '../platform/desktop/desktop_ports.dart';
-import '../platform/ports/ports.dart';
-import '../sfx/sfx.dart';
-import '../sfx/sound_bank.dart';
-import '../sfx/synth_sfx.dart';
-import '../session/notifier.dart';
-import '../session/connection.dart' show Connection;
-import '../session/identity.dart' show ClientIdentity;
-import '../session/session_coordinator.dart';
-import '../widgets/avatar_pipeline.dart';
-import 'connect_prefs.dart';
-import 'server_isolate.dart';
-import 'settings.dart';
-
-enum AppRoute {
-  home,
-  session,
-}
-
-enum ConnectMode { host, join }
-
-/// Both Home cards prefill from this. [host]/[port]/[secret] belong to
-/// the Join card, [hostPort]/[hostSecret] to the Host card.
-class ConnectForm {
-  String host;
-  String port;
-  String secret;
-  String hostPort;
-  String hostSecret;
-  String name;
-  String avatarPath;
-  String mediaPath;
-  String linkUrl;
-  ConnectForm({
-    this.host = '127.0.0.1',
-    this.port = '8080',
-    this.secret = '',
-    this.hostPort = '8080',
-    this.hostSecret = '',
-    this.name = '',
-    this.avatarPath = '',
-    this.mediaPath = '',
-    this.linkUrl = '',
-  });
-
-  ConnectForm copy() => ConnectForm(
-        host: host,
-        port: port,
-        secret: secret,
-        hostPort: hostPort,
-        hostSecret: hostSecret,
-        name: name,
-        avatarPath: avatarPath,
-        mediaPath: mediaPath,
-        linkUrl: linkUrl,
-      );
-}
-
-const connectKeyHostPort = 'hostPort';
-const connectKeyHostSecret = 'hostSecret';
-const connectKeyRecents = 'recents';
-const maxRecentServers = 6;
-
-/// A server the user got into, shown as a Recent chip on Home. Hosted
-/// entries refill the Host card; joined ones join in one click.
-class RecentServer {
-  final bool hosted;
-  final String host;
-  final String port;
-  final String secret;
-  const RecentServer(
-      {required this.hosted,
-      required this.host,
-      required this.port,
-      this.secret = ''});
-
-  String get key => hosted ? 'host:$port' : '${host.toLowerCase()}:$port';
-
-  Map<String, Object> toJson() =>
-      {'hosted': hosted, 'host': host, 'port': port, 'secret': secret};
-
-  static RecentServer? fromJson(Object? j) {
-    if (j is! Map) return null;
-    final host = j['host'], port = j['port'], secret = j['secret'];
-    if (host is! String || port is! String) return null;
-    return RecentServer(
-      hosted: j['hosted'] == true,
-      host: host,
-      port: port,
-      secret: secret is String ? secret : '',
-    );
-  }
-}
-
-/// Newest first, one entry per server, capped at [maxRecentServers].
-List<RecentServer> pushRecent(List<RecentServer> list, RecentServer s) => [
-      s,
-      ...list.where((r) => r.key != s.key),
-    ].take(maxRecentServers).toList();
-
-String encodeRecents(List<RecentServer> list) =>
-    jsonEncode([for (final r in list) r.toJson()]);
-
-List<RecentServer> decodeRecents(Object? raw) {
-  if (raw is! String) return const [];
-  try {
-    final list = jsonDecode(raw);
-    if (list is! List) return const [];
-    return [
-      for (final j in list) ?RecentServer.fromJson(j),
-    ].take(maxRecentServers).toList();
-  } catch (_) {
-    return const [];
-  }
-}
-
-/// Before recents existed only the last form was stored: a saved remote
-/// address becomes the first Recent chip.
-List<RecentServer> migrateRecents(
-    {required bool hadForm,
-    required String host,
-    required String port,
-    required String secret}) {
-  final h = host.trim().toLowerCase();
-  if (!hadForm || h.isEmpty || h == '127.0.0.1' || h == 'localhost') {
-    return const [];
-  }
-  return [RecentServer(hosted: false, host: host.trim(), port: port, secret: secret)];
-}
-
-/// The hosted server died during setup; shown on the Host card.
-class ServerCrashed implements Exception {
-  final String cause;
-  const ServerCrashed(this.cause);
-  @override
-  String toString() => 'server crashed: $cause';
-}
-
-/// A fresh per-hosting key: the app's own client sends it in hello to be
-/// recognised as the host (`members[].host`).
-String newHostKey() {
-  final r = Random.secure();
-  return base64Url.encode([for (var i = 0; i < 24; i++) r.nextInt(256)]);
-}
-
-class SessionState {
-  static final SessionState instance = SessionState._();
-  SessionState._();
-
-  final route = signal(AppRoute.home);
-  final recents = signal<List<RecentServer>>(const []);
-  /// Owns the app's audio device ([SynthSfx.dispose] on close).
-  final SynthSfx sfx = SynthSfx(
-    volume: () => AppSettings.instance.soundVolume.peek(),
-    // A nudge is an explicit poke: it ignores its switch (not the volume).
-    enabled: (k) => k == SfxKind.nudge || !AppSettings.instance.soundsOff.peek().contains(k.name),
-    presetFor: soundPresetFor,
-  );
-  /// The platform (window, links, folders, yt-dlp, notifications).
-  final Ports ports = desktopPorts();
-  /// Every toast, sound, system notification and activity-log line goes
-  /// through it.
-  late final Notifier notifier = Notifier(
-    sfx: sfx,
-    attention: ports.shell.requestAttention,
-    system: ports.notifications,
-    focusWindow: ports.shell.focus,
-    prefs: () => AppSettings.instance.notifyPrefs,
-  );
-  /// The link to the server; lost/back go to the notifier.
-  /// The link to the server, with this install's stored identity
-  /// (`hello.client` / `seq`); lost/back go to the notifier.
-  late final Connection connection = Connection(notify: notifier.notify, identity: ClientIdentity.stored());
-  late final SessionCoordinator coordinator =
-      SessionCoordinator(notifier: notifier, connection: connection, ytDlp: ports.links);
-  final lastForm = ConnectForm();
-  JellyfinAccounts get jellyfin => JellyfinAccounts.instance;
-  /// Set when the hosted server died mid-session; Home shows it on the
-  /// Host card and clears it.
-  final serverCrash = signal<String?>(null);
-  /// In a solo session: this app's own server on 127.0.0.1, only you in
-  /// it. Hosting from it ([host]) keeps what plays and where.
-  final solo = signal(false);
-  /// The joined server's own name (`/health`), '' until known or when it
-  /// only has the default name.
-  final serverLabel = signal('');
-  /// The server's Starsync version: a hosted (or solo) server is this
-  /// app's own; a joined one's comes from its `/health`; '' until known.
-  final serverVersion = signal('');
-  /// A solo session is becoming a hosted one: the player has nothing open
-  /// until the media is up again on the new server.
-  final switching = signal(false);
-  ConnectParams? _soloParams;
-
-  /// The app's yt-dlp folder for the hosted server; '' (the server's own
-  /// default) when the app-support folder is not available.
-  static Future<String> _sharedYtDlpDir() async {
-    try {
-      return (await instance.ports.links.ytDlp).dir;
-    } catch (_) {
-      return '';
-    }
-  }
-  ServerIsolate? _server;
-  String? _setupCrash;
-
-  @visibleForTesting
-  ServerIsolate? get hostedServer => _server;
-  // Bumped by host/join/cancelPending: a cancelled setup notices at its
-  // next step and unwinds instead of connecting.
-  int _op = 0;
-
-  Future<void> loadForm() async {
-    final box = await openConnectFormBox();
-    lastForm
-      ..host = readString(box, connectKeyHost, '127.0.0.1')
-      ..port = readString(box, connectKeyPort, '8080')
-      ..secret = readString(box, connectKeySecret, '');
-    // Old installs had one port/password for both modes.
-    lastForm
-      ..hostPort = readString(box, connectKeyHostPort, lastForm.port)
-      ..hostSecret = readString(box, connectKeyHostSecret, lastForm.secret)
-      ..name = readString(box, connectKeyName, '')
-      ..avatarPath = readString(box, connectKeyAvatarPath, '')
-      ..mediaPath = readString(box, connectKeyMediaPath, '')
-      ..linkUrl = readString(box, connectKeyLinkUrl, '');
-    recents.value = box.containsKey(connectKeyRecents)
-        ? decodeRecents(box.get(connectKeyRecents))
-        : migrateRecents(
-            hadForm: box.containsKey(connectKeyHost),
-            host: lastForm.host,
-            port: lastForm.port,
-            secret: lastForm.secret);
-  }
-
-  Future<void> saveForm() async {
-    final box = connectFormBoxIfOpen() ?? await openConnectFormBox();
-    await box.putAll({
-      connectKeyHost: lastForm.host,
-      connectKeyPort: lastForm.port,
-      connectKeySecret: lastForm.secret,
-      connectKeyHostPort: lastForm.hostPort,
-      connectKeyHostSecret: lastForm.hostSecret,
-      connectKeyName: lastForm.name,
-      connectKeyAvatarPath: lastForm.avatarPath,
-      connectKeyMediaPath: lastForm.mediaPath,
-      connectKeyLinkUrl: lastForm.linkUrl,
-      connectKeyRecents: encodeRecents(recents.peek()),
-    });
-  }
-
-  Future<String> loadAvatar(String path) => encodeAvatar(path);
-
-  /// Called by Home after a host/join got through.
-  Future<void> rememberServer(RecentServer server) async {
-    recents.value = pushRecent(recents.peek(), server);
-    await _saveFormQuietly();
-  }
-
-  Future<void> forgetServer(RecentServer server) async {
-    recents.value = [
-      for (final r in recents.peek())
-        if (r.key != server.key) r,
-    ];
-    await _saveFormQuietly();
-  }
-
-  /// Hosts a server friends can join. From a solo session it keeps the
-  /// media and position: the solo server goes, the new one gets the same
-  /// pick, seeked to where it was; if hosting fails, solo comes back.
-  Future<void> host(ConnectParams params, ConnectForm form) async {
-    if (!solo.peek()) return _host(params, form: form);
-    final carry = _invited = _carry();
-    switching.value = true;
-    try {
-      await coordinator.leave();
-      await stopServer();
-      solo.value = false;
-      coordinator.solo = false;
-      try {
-        await _host(params, form: form);
-      } catch (_) {
-        // Not hosted (failed or cancelled): back to solo, same media.
-        try {
-          await _host(_soloParams ?? params, soloSession: true);
-          if (carry != null) await _resume(carry);
-        } catch (e) {
-          debugPrint('back to solo failed: $e');
-          await leave();
-        }
-        rethrow;
-      }
-      try {
-        if (carry != null) await _resume(carry);
-      } catch (e) {
-        coordinator.notify(ActionFailed("couldn't put it up again: $e"));
-      }
-    } finally {
-      switching.value = false;
-    }
-  }
-
-  /// What an Invite from solo carried over, for [cancelInvite].
-  ({PickedMedia pick, double position})? _invited;
-
-  /// Invite cancelled after the hosted server already came up: back to
-  /// solo with the same media, not out of the session.
-  Future<void> cancelInvite() async {
-    final carry = _invited;
-    switching.value = true;
-    try {
-      await coordinator.leave();
-      await stopServer();
-      await _host(_soloParams!, soloSession: true);
-      if (carry != null) await _resume(carry);
-    } catch (e) {
-      debugPrint('back to solo failed: $e');
-      await leave();
-    } finally {
-      switching.value = false;
-    }
-  }
-
-  /// Watch alone: the same hosted path, on 127.0.0.1 and a free port, no
-  /// password, nothing put up yet. Nobody else can reach it.
-  Future<void> startSolo(ConnectParams params) async {
-    if (route.peek() == AppRoute.session) return;
-    _soloParams = params;
-    await _host(params, soloSession: true);
-  }
-
-  ({PickedMedia pick, double position})? _carry() {
-    final pick = coordinator.lastPick;
-    if (pick == null || coordinator.serverState.peek()?.media == null) return null;
-    final pos = coordinator.playback.positionSecs;
-    return (pick: pick, position: pos.isFinite && pos > 0 ? pos : 0.0);
-  }
-
-  /// Puts [carry] up on the server just joined and seeks to its position
-  /// once the swap shows in a state.
-  Future<void> _resume(({PickedMedia pick, double position}) carry) async {
-    final before = coordinator.serverState.peek()?.mediaId ?? 0;
-    final error = await coordinator.swapPicked(carry.pick);
-    if (error != null) throw StateError(error);
-    if (carry.position < 1) return;
-    final landed = Completer<void>();
-    final stop = effect(() {
-      final r = coordinator.serverState.value;
-      if (r != null && r.media != null && r.mediaId > before && !landed.isCompleted) landed.complete();
-    });
-    try {
-      await landed.future.timeout(const Duration(seconds: 20));
-      coordinator.connection.sendSeek(carry.position);
-    } on TimeoutException {
-      debugPrint('resume: the media did not come up; not seeking');
-    } finally {
-      stop();
-    }
-  }
-
-  Future<void> _host(ConnectParams params, {ConnectForm? form, bool soloSession = false}) async {
-    final op = ++_op;
-    if (form != null) _rememberForm(form);
-    try {
-      await stopServer();
-      if (op != _op) throw const ConnectCancelled();
-      final hostKey = newHostKey();
-      _setupCrash = null;
-      // A pasted Jellyfin link goes up as a ref like a browser pick.
-      final media = params.media ??
-          (params.linkUrl.isEmpty ? null : await mediaForLink(jellyfin, params.linkUrl));
-      if (op != _op) throw const ConnectCancelled();
-      // Guests without an account watch through the server, with the
-      // host's own sign-in (the hosted item's server, else the default).
-      await jellyfin.ensureLoaded(validate: false);
-      final relay = relayCredentialFor(jellyfin, serverId: media?.jellyfin?.serverId);
-      late final ServerIsolate server;
-      try {
-        server = await ServerIsolate.start(
-          AppConfig(
-            port: soloSession ? 0 : params.port,
-            secret: soloSession ? '' : params.secret,
-            name: 'server',
-            mediaPath: params.mediaPath,
-            hostKey: hostKey,
-            jellyfin: relay,
-            ytDlpDir: await _sharedYtDlpDir(),
-          ),
-          loopbackOnly: soloSession,
-          // Its session log (every member's shared diagnostics and its own
-          // records) goes next to the app's; not for a solo session.
-          logDir: soloSession ? null : appLogDir,
-          // Its records join the app's log as `server.<logger>`.
-          onLog: (line) => relogLine('server', line),
-          onCrash: (cause) => _onServerCrash(server, cause),
-        );
-      } catch (e, st) {
-        debugPrint('server start failed: $e\n$st');
-        rethrow;
-      }
-      if (op != _op) {
-        await server.stop();
-        throw const ConnectCancelled();
-      }
-      _server = server;
-      coordinator.hostFile = (path) async =>
-          identical(_server, server) ? server.setFile(path) : null;
-      serverVersion.value = appVersion;
-      try {
-        await coordinator.connect(ConnectParams(
-          host: '127.0.0.1',
-          port: server.port,
-          secret: soloSession ? '' : params.secret,
-          name: params.name,
-          avatar: params.avatar,
-          hostKey: hostKey,
-          media: media,
-        ));
-        if (op != _op) throw const ConnectCancelled();
-      } catch (e) {
-        // Own join failed or was cancelled: don't leave the port open.
-        if (identical(_server, server)) await stopServer();
-        final crash = _setupCrash;
-        if (crash != null && e is! ConnectCancelled) throw ServerCrashed(crash);
-        rethrow;
-      }
-      solo.value = soloSession;
-      coordinator.solo = soloSession;
-      route.value = AppRoute.session;
-    } finally {
-      if (form != null) await _saveFormQuietly();
-    }
-  }
-
-  /// The server isolate died without being stopped. In a session: show it
-  /// and leave. During setup the own join fails and [host] reports it.
-  void _onServerCrash(ServerIsolate server, String cause) {
-    if (!identical(_server, server)) return;
-    final message = 'server crashed: $cause';
-    debugPrint('[server] $message');
-    if (route.peek() != AppRoute.session) {
-      _setupCrash = cause;
-      return;
-    }
-    serverCrash.value = message;
-    unawaited(leave().catchError((Object e) => debugPrint('leave after crash failed: $e')));
-  }
-
-  Future<void> join(ConnectParams params, ConnectForm form) async {
-    final op = ++_op;
-    _rememberForm(form);
-    try {
-      await coordinator.connect(params);
-      if (op != _op) throw const ConnectCancelled();
-      route.value = AppRoute.session;
-      serverLabel.value = '';
-      serverVersion.value = '';
-      unawaited(probeHealth(params.host, '${params.port}', defaultHealthGet).then((h) {
-        if (op != _op || !h.online) return;
-        // 'server' is the dedicated server's default --name: not a name.
-        if (h.name.isNotEmpty && h.name != 'server') serverLabel.value = h.name;
-        serverVersion.value = h.version;
-      }).catchError((Object _) {}));
-    } finally {
-      await _saveFormQuietly();
-    }
-  }
-
-  /// Cancel button during setup: abort whichever step is running (server
-  /// start, player init, socket dial) without connecting.
-  Future<void> cancelPending() async {
-    _op++;
-    try {
-      await coordinator.cancelConnect();
-    } catch (_) {}
-    // Solo becoming hosted: [host] stops what it started and goes back
-    // to solo itself.
-    if (!switching.peek()) await stopServer();
-  }
-
-  /// Saved whatever the outcome: a failed join is exactly when the user
-  /// wants the form back.
-  Future<void> _saveFormQuietly() async {
-    try {
-      await saveForm();
-    } catch (e, st) {
-      debugPrint('save connect form failed: $e\n$st');
-    }
-  }
-
-  void _rememberForm(ConnectForm form) {
-    lastForm
-      ..host = form.host
-      ..port = form.port
-      ..secret = form.secret
-      ..hostPort = form.hostPort
-      ..hostSecret = form.hostSecret
-      ..name = form.name
-      ..avatarPath = form.avatarPath
-      ..mediaPath = form.mediaPath
-      ..linkUrl = form.linkUrl;
-  }
-
-  Future<void> stopServer() async {
-    coordinator.hostFile = null;
-    final server = _server;
-    _server = null;
-    await server?.stop();
-  }
-
-  /// Out of the session (Leave, the app closing). [bye] false: Update
-  /// and restart, the restarted app takes the member back within its grace.
-  Future<void> leave({bool bye = true}) async {
-    await coordinator.leave(bye: bye);
-    await stopServer();
-    solo.value = false;
-    coordinator.solo = false;
-    serverLabel.value = '';
-    serverVersion.value = '';
-    route.value = AppRoute.home;
-  }
-}
-
-/// The sound set [kind] plays from: its own pick in Settings, else the
-/// overall one.
-SoundPreset soundPresetFor(SfxKind kind) {
-  final s = AppSettings.instance;
-  final name = s.soundPresetFor.peek()[kind.name] ?? s.soundPreset.peek();
-  return SoundPreset.values.where((p) => p.name == name).firstOrNull ?? defaultPreset;
-}

apps/desktop/lib/src/widgets/app_keys.dart

@@ -2,7 +2,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 
 import '../shell/mark_problem.dart';
-import '../state/session_state.dart';
+import '../app/app_graph.dart';
 import 'text_focus.dart';
 
 /// Tab and Shift+Tab never move focus, and Space never presses the
@@ -61,13 +61,13 @@ class _AppKeysState extends State<AppKeys> {
       return true;
     }
     if (key != LogicalKeyboardKey.space && key != LogicalKeyboardKey.tab) return false;
-    if (SessionState.instance.route.peek() != AppRoute.session) return false;
+    if (!AppScope.of(context).navigation.online.peek()) return false;
     if (ModalRoute.of(context)?.isCurrent == false) return false;
     if (textInputFocused()) return false;
     final keys = HardwareKeyboard.instance;
     if (keys.isControlPressed || keys.isAltPressed || keys.isMetaPressed) return false;
     if (key == LogicalKeyboardKey.space) {
-      (widget.onToggleReady ?? SessionState.instance.coordinator.toggleReady)();
+      (widget.onToggleReady ?? AppScope.of(context).coordinator.toggleReady)();
       return true;
     }
     final toggles = AppKeys._chatToggles;

apps/desktop/lib/src/widgets/copy_open.dart

@@ -1,8 +1,8 @@
-import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
+import 'package:flutter/widgets.dart';
 
 import '../session/notifier.dart' show AppEvent, Copied, CopyFailed, noticeFor;
-import '../state/session_state.dart';
+import '../app/app_graph.dart';
 
 // Reusing what the app shows elsewhere: copying a link or a title, opening
 // a page in the browser. One wording and one confirmation (a small toast)
@@ -21,27 +21,36 @@ abstract final class ReuseText {
 @visibleForTesting
 void Function(String text)? debugReuseToast;
 
-void _notify(AppEvent event) {
+void Function(AppEvent event) _notifier(BuildContext context) {
   final debug = debugReuseToast;
-  if (debug != null) return debug(noticeFor(event).toast ?? '');
-  SessionState.instance.coordinator.notify(event);
+  if (debug != null) return (event) => debug(noticeFor(event).toast ?? '');
+  return AppScope.of(context).notifier.notify;
 }
 
 /// Puts [text] on the clipboard and confirms it with a toast ([done]:
 /// its text, e.g. "Link copied").
-Future<void> copyToClipboard(String text, {String done = 'Copied'}) async {
+Future<void> copyToClipboard(BuildContext context, String text, {String done = 'Copied'}) async {
+  final notify = _notifier(context);
   try {
     await Clipboard.setData(ClipboardData(text: text));
   } catch (_) {
-    _notify(const CopyFailed());
+    notify(const CopyFailed());
     return;
   }
-  _notify(Copied(done));
+  notify(Copied(done));
 }
 
 /// Opens [url] in the browser; when none opens, copies it instead and
 /// says so.
-Future<void> openLink(String url) async {
-  if (await SessionState.instance.ports.urls.open(url)) return;
-  await copyToClipboard(url, done: "Couldn't open a browser — link copied");
+Future<void> openLink(BuildContext context, String url) async {
+  final urls = AppScope.of(context).ports.urls;
+  final notify = _notifier(context);
+  if (await urls.open(url)) return;
+  try {
+    await Clipboard.setData(ClipboardData(text: url));
+  } catch (_) {
+    notify(const CopyFailed());
+    return;
+  }
+  notify(const Copied("Couldn't open a browser — link copied"));
 }

apps/desktop/lib/src/widgets/window_buttons.dart

@@ -1,6 +1,6 @@
 import 'package:flutter/material.dart';
 
-import '../state/session_state.dart';
+import '../app/app_graph.dart';
 
 class WindowButtons extends StatefulWidget {
   final FocusNode? focusNode;
@@ -18,7 +18,7 @@ class WindowButtons extends StatefulWidget {
 }
 
 class _WindowButtonsState extends State<WindowButtons> {
-  final _shell = SessionState.instance.ports.shell;
+  late final _shell = AppScope.of(context).ports.shell;
   bool _maximized = false;
   late final void Function() _stopWatch;
 
@@ -53,8 +53,9 @@ class _WindowButtonsState extends State<WindowButtons> {
 
   Future<void> _close() async {
     try {
-      await SessionState.instance.coordinator.leave();
-      await SessionState.instance.stopServer();
+      final graph = AppScope.of(context);
+      await graph.navigation.leave();
+      await graph.yourServer.stop();
     } catch (_) {}
     await _shell.requestClose();
   }
@@ -133,7 +134,7 @@ class WindowDragArea extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final shell = SessionState.instance.ports.shell;
+    final shell = AppScope.of(context).ports.shell;
     return GestureDetector(
       behavior: HitTestBehavior.translucent,
       onPanStart: (_) => shell.startDragging(),

apps/desktop/test/app_keys_test.dart

@@ -3,17 +3,23 @@ import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:sync_relay_core/core.dart';
 import 'package:starsync/src/shell/app_shell.dart';
-import 'package:starsync/src/state/session_state.dart';
 import 'package:starsync/src/update/update_controller.dart';
 import 'package:starsync/src/widgets/app_keys.dart';
 import 'package:starsync/src/widgets/text_focus.dart';
 
+import 'package:starsync/src/session/navigation.dart' show Place;
+
+import 'test_graph.dart';
+
+/// This file's composition root (see test_graph.dart).
+final _graph = testGraph();
+
 void main() {
-  final session = SessionState.instance;
+  final session = _graph;
   final coord = session.coordinator;
 
   tearDown(() {
-    session.route.value = AppRoute.home;
+    session.navigation.place.value = Place.none;
     coord.serverState.value = null;
   });
 
@@ -24,7 +30,7 @@ void main() {
     tester.view.devicePixelRatio = 1;
     addTearDown(tester.view.reset);
     var readies = 0;
-    await tester.pumpWidget(MaterialApp(
+    await tester.pumpWidget(scoped(_graph, MaterialApp(
       theme: ThemeData.dark(),
       shortcuts: appShortcuts,
       home: AppKeys(
@@ -36,7 +42,7 @@ void main() {
           videoBuilder: (context, controls) => const SizedBox(),
         ),
       ),
-    ));
+    )));
     coord.serverState.value = StateBroadcast(
       eventId: 1,
       transport: 'held',
@@ -45,7 +51,7 @@ void main() {
       mediaId: 0,
       members: [MemberView(id: 'a', name: 'Alex', ready: false, inSet: false, buffered: 0)],
     );
-    session.route.value = AppRoute.session;
+    session.navigation.place.value = Place.friend;
     await tester.pumpAndSettle();
     final panel = find.byKey(const ValueKey('chat-panel'));
 
@@ -67,11 +73,11 @@ void main() {
   });
 
   testWidgets('Ctrl+Shift+B opens Mark a problem; Esc closes it unmarked', (tester) async {
-    await tester.pumpWidget(MaterialApp(
+    await tester.pumpWidget(scoped(_graph, MaterialApp(
       theme: ThemeData.dark(),
       shortcuts: appShortcuts,
       home: const AppKeys(child: Scaffold(body: SizedBox())),
-    ));
+    )));
     final card = find.byKey(const ValueKey('mark-problem-card'));
     await tester.sendKeyDownEvent(LogicalKeyboardKey.controlLeft);
     await tester.sendKeyDownEvent(LogicalKeyboardKey.shiftLeft);

apps/desktop/test/controls_model_test.dart

@@ -7,9 +7,13 @@ import 'package:starsync/src/controls/model/controls_model.dart';
 import 'package:starsync/src/controls/model/controls_prefs.dart';
 import 'package:starsync/src/controls/session_controls.dart';
 import 'package:starsync/src/playback/media_marks.dart';
-import 'package:starsync/src/state/session_state.dart';
 import 'package:starsync/src/state/settings.dart';
 
+import 'test_graph.dart';
+
+/// This file's composition root (see test_graph.dart).
+final _graph = testGraph();
+
 // The controls model and its layout spec: which controls the bar has, in
 // which order, what goes to ⚙; and both skins drawing the same order.
 
@@ -64,7 +68,7 @@ void main() {
       final all = menuActions(const ControlsSnapshot(hasChapters: true, hasDuration: true, hasLink: true), none);
       expect(all.first, ControlAction.chapters);
       expect(all, containsAllInOrder([ControlAction.skipForward, ControlAction.copyLink]));
-      expect(menuActions(const ControlsSnapshot(solo: true), none), isNot(contains(ControlAction.markAllReady)),
+      expect(menuActions(const ControlsSnapshot(alone: true), none), isNot(contains(ControlAction.markAllReady)),
           reason: 'nobody to mark ready');
     });
 
@@ -74,7 +78,7 @@ void main() {
       expect(controlIcon(BarControl.playPause, const ControlsSnapshot(play: PlayState.waiting)), Icons.check_rounded);
       expect(controlTooltip(BarControl.playPause, const ControlsSnapshot(play: PlayState.playing)),
           'Pause for everyone (Space)');
-      expect(controlTooltip(BarControl.playPause, const ControlsSnapshot(solo: true)), 'Play (Space)');
+      expect(controlTooltip(BarControl.playPause, const ControlsSnapshot(alone: true)), 'Play (Space)');
     });
 
     test('episode buttons: the label and the keys', () {
@@ -98,7 +102,7 @@ void main() {
 
   group('both skins draw the model', () {
     final s = AppSettings.instance;
-    final coord = SessionState.instance.coordinator;
+    final coord = _graph.coordinator;
 
     tearDown(() {
       s.controlsSkin.value = ControlsSkin.standard;
@@ -131,13 +135,13 @@ void main() {
         shown.dispose();
         hold.dispose();
       });
-      await tester.pumpWidget(MaterialApp(
+      await tester.pumpWidget(scoped(_graph, MaterialApp(
         theme: ThemeData.dark(),
         home: Scaffold(
           backgroundColor: Colors.black,
           body: SessionControls(model: model, shown: shown, hold: hold, onDoubleClick: () {}),
         ),
-      ));
+      )));
       await tester.pump();
       return model;
     }

apps/desktop/test/coord_presence_test.dart

@@ -18,9 +18,13 @@ import 'package:starsync/src/session/identity.dart';
 import 'package:starsync/src/session/notifier.dart';
 import 'package:starsync/src/session/session_coordinator.dart';
 import 'package:starsync/src/sfx/sfx.dart';
-import 'package:starsync/src/state/session_state.dart';
 import 'package:starsync/src/sync/sync_client.dart';
 
+import 'test_graph.dart';
+
+/// This file's composition root (see test_graph.dart).
+final _graph = testGraph();
+
 final _tmp = Platform.environment['WT_TEST_TMP'] ?? Directory.systemTemp.path;
 
 Future<void> _poll(
@@ -376,22 +380,27 @@ void main() {
     }
   });
 
-  test('cancelling a host setup releases the port', timeout: const Timeout(Duration(minutes: 1)), () async {
+  test('stop sharing releases the port; stopping your server frees its own', timeout: const Timeout(Duration(minutes: 1)),
+      () async {
     Hive.init('$_tmp/hive_coord_test');
     final probe = await ServerSocket.bind(InternetAddress.anyIPv4, 0);
     final port = probe.port;
     await probe.close();
-    final session = SessionState.instance;
+    final yours = _graph.yourServer;
+    _graph.forms.form
+      ..hostPort = '$port'
+      ..hostSecret = '';
     try {
-      final pending = session.host(ConnectParams(host: '', port: port, secret: '', name: 'host'), ConnectForm());
-      await session.cancelPending();
-      await expectLater(pending, throwsA(isA<ConnectCancelled>()));
-      expect(session.route.peek(), isNot(AppRoute.session));
+      final own = await yours.start(name: 'me');
+      expect((await yours.invite()).port, port);
+      await yours.stopSharing();
       final rebind = await ServerSocket.bind(InternetAddress.anyIPv4, port);
       await rebind.close();
+      await yours.stop();
+      final again = await ServerSocket.bind(InternetAddress.loopbackIPv4, own);
+      await again.close();
     } finally {
-      await session.coordinator.leave(silent: true);
-      await session.stopServer();
+      await yours.stop();
     }
   });
 

apps/desktop/test/delivery_test.dart

@@ -7,6 +7,11 @@ import 'package:sync_relay_core/core.dart';
 import 'package:starsync/src/session/delivery.dart';
 import 'package:starsync/src/shell/delivery_line.dart';
 
+import 'test_graph.dart';
+
+/// This file's composition root (see test_graph.dart).
+final _graph = testGraph();
+
 MemberView _m(String id, String name, {double buffered = 30, bool host = false, int rate = 0}) =>
     MemberView(id: id, name: name, ready: true, inSet: true, buffered: buffered, host: host, rate: rate);
 
@@ -134,7 +139,7 @@ void main() {
     final r = _state(
         _relayed(const MediaRelay(source: 'm1', live: true, rate: 1200000, need: 2300000)), [foxyz, bob, ann]);
     final d = deliveryOf(r, selfId: 'm2')!;
-    await tester.pumpWidget(MaterialApp(
+    await tester.pumpWidget(scoped(_graph, MaterialApp(
       theme: ThemeData.dark(),
       home: Scaffold(
         body: Center(
@@ -147,7 +152,7 @@ void main() {
           ),
         ),
       ),
-    ));
+    )));
     await tester.pumpAndSettle();
     expect(find.text("Foxyz's upload is slower than the video"), findsOneWidget);
     expect(find.byKey(const ValueKey('headroom-bar')), findsOneWidget);

apps/desktop/test/files_page_test.dart

@@ -13,6 +13,11 @@ import 'package:starsync/src/files/thumbnails.dart';
 import 'package:starsync/src/files/ui/file_tiles.dart';
 import 'package:starsync/src/files/ui/files_page.dart';
 
+import 'test_graph.dart';
+
+/// This file's composition root (see test_graph.dart).
+final _graph = testGraph();
+
 // The Files page over a real (tiny) folder tree: the scan runs in-line
 // instead of in an isolate and thumbnails come from a fake loader, so
 // nothing here decodes video.
@@ -46,7 +51,7 @@ Future<void> frames(WidgetTester tester, [int n = 10]) async {
 Future<void> pumpPage(
   WidgetTester tester, {
   Size size = const Size(1280, 800),
-  bool solo = false,
+  bool alone = false,
   bool relayed = false,
   Future<String?> Function(String path)? onPlay,
   ThumbnailLoader? thumbnails,
@@ -55,10 +60,10 @@ Future<void> pumpPage(
   tester.view.physicalSize = size;
   tester.view.devicePixelRatio = 1;
   addTearDown(tester.view.reset);
-  await tester.pumpWidget(MaterialApp(
+  await tester.pumpWidget(scoped(_graph, MaterialApp(
     home: Scaffold(
       body: FilesPage(
-        solo: solo,
+        alone: alone,
         relayed: relayed,
         onPlay: onPlay ?? (_) async => null,
         thumbnails: thumbnails ?? fakeThumb,
@@ -67,7 +72,7 @@ Future<void> pumpPage(
         pickFolder: pickFolder,
       ),
     ),
-  ));
+  )));
   await frames(tester);
 }
 
@@ -242,7 +247,7 @@ void main() {
     tester.view.physicalSize = const Size(1280, 800);
     tester.view.devicePixelRatio = 1;
     addTearDown(tester.view.reset);
-    await tester.pumpWidget(MaterialApp(
+    await tester.pumpWidget(scoped(_graph, MaterialApp(
       home: Scaffold(
         body: FilesPage(
           relayed: false,
@@ -253,7 +258,7 @@ void main() {
           store: store,
         ),
       ),
-    ));
+    )));
     await frames(tester);
     await openFolder(tester, 'anime');
     await openSeries(tester);

apps/desktop/test/home_test.dart

@@ -1,7 +1,5 @@
-// restructure: rewrite in step 3 (Your server): hosted recents and the host
-// card; the rest stays.
 import 'dart:convert';
-import 'dart:io' show Platform;
+import 'dart:io' show Platform, SocketException;
 
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
@@ -12,13 +10,22 @@ import 'package:starsync/src/screens/home/health_probe.dart';
 import 'package:starsync/src/screens/home/media_picker.dart';
 import 'package:starsync/src/screens/home/update_indicator.dart';
 import 'package:starsync/src/shell/app_shell.dart';
-import 'package:starsync/src/shell/library_link.dart' show soloPlayHint;
-import 'package:starsync/src/state/session_state.dart';
+import 'package:starsync/src/shell/library_link.dart' show alonePlayHint;
+import 'package:starsync/src/state/connect_prefs.dart';
 import 'package:starsync/src/state/settings.dart';
 import 'package:starsync/src/update/update_controller.dart';
 
+import 'package:starsync/src/session/connection.dart' show ConnClosed;
+import 'package:starsync/src/session/navigation.dart' show JoinFailed, Place;
+import 'package:starsync/src/session/session_coordinator.dart' show ConnectParams;
+
+import 'test_graph.dart';
+
+/// This file's composition root (see test_graph.dart).
+final _graph = testGraph();
+
 RecentServer join(String host, String port, [String secret = '']) =>
-    RecentServer(hosted: false, host: host, port: port, secret: secret);
+    RecentServer(host: host, port: port, secret: secret);
 
 void main() {
   group('recent servers', () {
@@ -35,21 +42,12 @@ void main() {
       expect(list.where((r) => r.host == '10.0.0.4').length, 1);
     });
 
-    test('hosted entries are one per port, separate from joins', () {
-      var list = <RecentServer>[];
-      list = pushRecent(list, const RecentServer(hosted: true, host: '', port: '8080'));
-      list = pushRecent(list, join('127.0.0.1', '8080'));
-      list = pushRecent(list, const RecentServer(hosted: true, host: '', port: '8080', secret: 'x'));
-      expect(list.length, 2);
-      expect(list.first.secret, 'x');
-    });
-
-    test('round-trips and tolerates junk', () {
-      final list = [join('a.example', '9000', 's'), const RecentServer(hosted: true, host: '', port: '8080')];
+    test('round-trips and tolerates junk; hosted entries of older versions are dropped', () {
+      final list = [join('a.example', '9000', 's'), join('b.example', '8080')];
       final back = decodeRecents(encodeRecents(list));
       expect(back.map((r) => r.key), list.map((r) => r.key));
       expect(back.first.secret, 's');
-      expect(back.last.hosted, isTrue);
+      expect(decodeRecents('[{"hosted":true,"host":"","port":"8080"},{"host":"h","port":"1"}]').single.host, 'h');
       expect(decodeRecents('not json'), isEmpty);
       expect(decodeRecents(42), isEmpty);
       expect(decodeRecents('[{"host":1},{"host":"h","port":"1"}]').single.host, 'h');
@@ -79,8 +77,15 @@ void main() {
   });
 
   test('health parse: online, junk and protocol mismatch', () {
-    final ok = ServerHealth.parse(jsonEncode(
-        {'ok': true, 'name': 'Den', 'proto': RelayConstants.protoVersion, 'viewers': 2, 'version': '1.3.0'}));
+    final ok = ServerHealth.parse(jsonEncode({
+      'ok': true,
+      'name': 'Den',
+      'proto': RelayConstants.protoMax,
+      'protoMin': RelayConstants.protoMin,
+      'protoMax': RelayConstants.protoMax,
+      'viewers': 2,
+      'version': '1.3.0'
+    }));
     expect(ok.online, isTrue);
     expect(ok.name, 'Den');
     expect(ok.version, '1.3.0');
@@ -93,6 +98,73 @@ void main() {
     expect(healthUri('::1', '8080').toString(), 'http://[::1]:8080/health');
   });
 
+  group('version gate (/health)', () {
+    String body({required int min, required int max, String version = '', String name = ''}) =>
+        jsonEncode({'ok': true, 'name': name, 'proto': max, 'protoMin': min, 'protoMax': max, 'version': version});
+    const own = RelayConstants.protoMin;
+
+    test('older, newer, compatible', () {
+      final older = ServerHealth.parse(body(min: own - 2, max: own - 1, version: '1.2.1', name: "Bob's server"));
+      expect(older.fit, VersionFit.theyUpdate);
+      expect(versionGateText(older), "Bob's server runs Starsync 1.2.1 — they need to update");
+      final newer = ServerHealth.parse(body(min: RelayConstants.protoMax + 1, max: RelayConstants.protoMax + 2, version: '2.0.0'));
+      expect(newer.fit, VersionFit.youUpdate);
+      expect(versionGateText(newer), 'The server runs Starsync 2.0.0 — you need to update');
+      final overlap = ServerHealth.parse(body(min: own - 1, max: RelayConstants.protoMax + 3));
+      expect(overlap.fit, VersionFit.ok, reason: 'ranges that meet are fine');
+      // A proto 15 server says only `proto`.
+      final old = ServerHealth.parse('{"ok":true,"proto":15,"name":"server"}');
+      expect(old.fit, VersionFit.theyUpdate);
+      expect(versionGateText(old), 'The server runs an older Starsync — they need to update');
+      expect(ServerHealth.parse('{"ok":true}').fit, isNull, reason: 'unknown: let the hello decide');
+    });
+
+    test('a join stops at the gate, still at home, before connecting', () async {
+      final graph = testGraph(healthGet: (uri) async => body(min: own - 2, max: own - 1, version: '1.2.1'));
+      await expectLater(
+          graph.navigation.join(const ConnectParams(host: 'old.example', port: 8080, secret: '', name: 'Me')),
+          throwsA(isA<VersionGateRefused>()
+              .having((e) => e.youUpdate, 'youUpdate', isFalse)
+              .having((e) => e.message, 'message', contains('they need to update'))));
+      expect(graph.connection.state.peek(), isA<ConnClosed>(), reason: 'never dialled');
+      final newer = testGraph(
+          healthGet: (uri) async => body(min: RelayConstants.protoMax + 1, max: RelayConstants.protoMax + 1));
+      await expectLater(newer.navigation.join(const ConnectParams(host: 'new.example', port: 8080, secret: '', name: 'Me')),
+          throwsA(isA<VersionGateRefused>().having((e) => e.youUpdate, 'youUpdate', isTrue)));
+      final offline = testGraph(healthGet: (uri) async => throw const SocketException('refused'));
+      await expectLater(offline.navigation.join(const ConnectParams(host: 'gone.example', port: 8080, secret: '', name: 'Me')),
+          throwsA(isA<JoinFailed>()));
+    });
+
+    testWidgets('the Join card says who has to update and offers the updater when it is you', (tester) async {
+      final graph = testGraph(
+          healthGet: (uri) async => body(min: RelayConstants.protoMax + 1, max: RelayConstants.protoMax + 1, version: '2.0.0'));
+      graph.forms.form.name = 'Me';
+      tester.view.physicalSize = const Size(1280, 800);
+      tester.view.devicePixelRatio = 1;
+      addTearDown(tester.view.reset);
+      await tester.pumpWidget(scoped(
+          graph,
+          MaterialApp(
+            theme: ThemeData.dark(),
+            home: AppShell(
+              updates: UpdateController(currentVersion: '0.0.0-dev'),
+              autoUpdateCheck: false,
+              windowControls: false,
+              healthGet: graph.navigation.healthGet,
+            ),
+          )));
+      await tester.pump();
+      await tester.tap(find.byKey(const ValueKey('strip-join')));
+      await tester.pumpAndSettle();
+      await tester.enterText(find.byKey(const ValueKey('join-address')), 'new.example');
+      await tester.tap(find.widgetWithText(FilledButton, 'Join').last);
+      await tester.pumpAndSettle();
+      expect(find.textContaining('you need to update'), findsOneWidget);
+      expect(find.byKey(const ValueKey('join-update')), findsOneWidget);
+    });
+  });
+
   test('pasting sorts links and paths into the right source', () {
     final c = MediaPickerController();
     expect(c.source, MediaKind.jellyfin);
@@ -118,7 +190,7 @@ void main() {
     tester.view.physicalSize = size;
     tester.view.devicePixelRatio = 1;
     addTearDown(tester.view.reset);
-    await tester.pumpWidget(MaterialApp(
+    await tester.pumpWidget(scoped(_graph, MaterialApp(
       theme: ThemeData.dark(),
       home: AppShell(
         updates: UpdateController(currentVersion: '0.0.0-dev'),
@@ -126,7 +198,7 @@ void main() {
         windowControls: false,
         healthGet: health ?? fakeHealth(const {}),
       ),
-    ));
+    )));
     await tester.pump();
   }
 
@@ -136,8 +208,8 @@ void main() {
   }
 
   setUp(() {
-    SessionState.instance.recents.value = const [];
-    SessionState.instance.route.value = AppRoute.home;
+    _graph.forms.recents.value = const [];
+    _graph.navigation.place.value = Place.none;
   });
 
   testWidgets('tabs and settings pages switch the body', (tester) async {
@@ -178,7 +250,7 @@ void main() {
   });
 
   testWidgets('Enter in the join card submits; errors show under it', (tester) async {
-    SessionState.instance.lastForm.name = '';
+    _graph.forms.form.name = '';
     await pumpShell(tester, const Size(1280, 720));
     await openCard(tester, 'strip-join');
     await tester.enterText(find.byKey(const ValueKey('join-address')), 'friend.example');
@@ -201,11 +273,10 @@ void main() {
   });
 
   testWidgets('recent rows show live status from /health', (tester) async {
-    SessionState.instance.recents.value = [
+    _graph.forms.recents.value = [
       join('alpha.example', '8080'),
       join('beta.example', '9000', 'pw'),
       join('gamma.example', '7000'),
-      const RecentServer(hosted: true, host: '', port: '8181'),
     ];
     await pumpShell(tester, const Size(1280, 900),
         health: fakeHealth({
@@ -226,8 +297,6 @@ void main() {
     expect(inRow('beta.example:9000', find.text('○ offline')), findsOneWidget);
     expect(inRow('beta.example:9000', find.text('beta.example')), findsOneWidget);
     expect(inRow('gamma.example:7000', find.text('needs update')), findsOneWidget);
-    // Hosted entries live on the Host card, not in the join list.
-    expect(find.byKey(const ValueKey('recent-host:8181')), findsNothing);
     // x forgets.
     await tester.tap(inRow('beta.example:9000', find.byTooltip('Forget')));
     await tester.pump();
@@ -242,13 +311,15 @@ void main() {
     expect(find.byKey(const ValueKey('join-row')), findsOneWidget);
   });
 
-  testWidgets('library offline: welcome band, sources that need nothing, Jellyfin optional', (tester) async {
+  testWidgets('library at home: welcome band, sources that need nothing, Jellyfin optional', (tester) async {
     await pumpShell(tester, const Size(1280, 900));
     // The three ways in, Join first; none needs Jellyfin.
     expect(find.byKey(const ValueKey('welcome-band')), findsOneWidget);
     expect(find.text('Watch together, in sync'), findsOneWidget);
     final join = tester.getTopLeft(find.byKey(const ValueKey('way-join')));
-    expect(join.dx, lessThan(tester.getTopLeft(find.byKey(const ValueKey('way-solo'))).dx));
+    expect(join.dx, lessThan(tester.getTopLeft(find.byKey(const ValueKey('way-invite'))).dx));
+    expect(find.text('Watch on your own'), findsOneWidget);
+    expect(find.text('Host'), findsNothing, reason: 'no Host: your server is always there');
     // No linked server: Files and Link first, Jellyfin as an optional card.
     expect(find.text('Pick something to watch'), findsOneWidget);
     expect(find.text('Add a Jellyfin server'), findsNothing);
@@ -262,25 +333,19 @@ void main() {
     await tester.pumpAndSettle();
     expect(find.text('Watch from a link'), findsOneWidget);
     // Alone: Play, no relay modes.
-    expect(find.text(soloPlayHint), findsOneWidget);
+    expect(find.text(alonePlayHint), findsOneWidget);
     expect(find.text('How the others get it'), findsNothing);
     expect(tester.takeException(), isNull);
   });
 
-  testWidgets('host without a name errors in the host card', (tester) async {
-    SessionState.instance.lastForm.name = '';
-    SessionState.instance.recents.value = [const RecentServer(hosted: true, host: '', port: '8181', secret: 's')];
+  testWidgets('pasting an invite into the address fills the port', (tester) async {
     await pumpShell(tester, const Size(1280, 900));
-    await openCard(tester, 'strip-host');
-    expect(find.text('No password — anyone can join'), findsOneWidget);
-    expect(find.text('You pick what to watch afterwards, in the library.'), findsOneWidget);
-    // A hosted port refills the fields.
-    await tester.tap(find.byKey(const ValueKey('recent-host:8181')));
+    await openCard(tester, 'strip-join');
+    await tester.enterText(find.byKey(const ValueKey('join-address')),
+        'Join me on Starsync: 192.168.1.20:9123 (ask me for the password) · Starsync 1.3.0');
     await tester.pump();
-    expect(find.text('No password — anyone can join'), findsNothing);
-    await tester.tap(find.widgetWithText(FilledButton, 'Host').last);
-    await tester.pumpAndSettle();
-    expect(find.textContaining('display name', findRichText: true), findsOneWidget);
+    expect(tester.widget<TextField>(find.byKey(const ValueKey('join-address'))).controller!.text, '192.168.1.20');
+    expect(tester.widget<TextField>(find.byKey(const ValueKey('join-port'))).controller!.text, '9123');
   });
 
   testWidgets('narrow window: strip, cards and library fit', (tester) async {
@@ -310,8 +375,8 @@ void main() {
           executablePath: '/nowhere/watch_together',
           restart: (_, _) async {});
       c.status.value = s;
-      await tester.pumpWidget(MaterialApp(
-          home: Scaffold(body: Column(children: [UpdateBar(controller: c)]))));
+      await tester.pumpWidget(scoped(_graph, MaterialApp(
+          home: Scaffold(body: Column(children: [UpdateBar(controller: c)])))));
       return c;
     }
 

apps/desktop/test/jellyfin_browser_test.dart

@@ -12,9 +12,14 @@ import 'package:starsync/src/jellyfin/browse_scope.dart';
 import 'package:starsync/src/jellyfin/picker_source.dart';
 import 'package:starsync/src/state/settings.dart';
 
+import 'test_graph.dart';
+
 import 'jellyfin_accounts_test.dart'
     show FakeJellyfin, arifuretaId, fixtureServerId, linkedAccounts, season2Id;
 
+/// This file's composition root (see test_graph.dart).
+final _graph = testGraph();
+
 Future<void> setSize(WidgetTester tester, Size size) async {
   tester.view.physicalSize = size;
   tester.view.devicePixelRatio = 1;
@@ -55,7 +60,7 @@ Future<(Picks, JellyfinAccounts, FakeJellyfin, BrowseController)> pumpBrowser(
   final controller = BrowseController(accounts, now: () => fixtureNow);
   addTearDown(controller.dispose);
   final picks = Picks();
-  await tester.pumpWidget(app(StatefulBuilder(
+  await tester.pumpWidget(scoped(_graph, app(StatefulBuilder(
     builder: (context, setState) => JellyfinBrowser(
       accounts: accounts,
       controller: controller,
@@ -63,7 +68,7 @@ Future<(Picks, JellyfinAccounts, FakeJellyfin, BrowseController)> pumpBrowser(
       onSelect: (s) => setState(() => picks.selected.add(s)),
       onPutUp: picks.putUp.add,
     ),
-  )));
+  ))));
   await settle(tester);
   return (picks, accounts, fake, controller);
 }
@@ -154,8 +159,8 @@ void main() {
     addTearDown(controller.dispose);
     AppSettings.instance.hideReReleases.value = true;
     addTearDown(() => AppSettings.instance.hideReReleases.value = true);
-    await tester.pumpWidget(app(JellyfinBrowser(
-        accounts: accounts, controller: controller, onSelect: (_) {}, onPutUp: (_) {})));
+    await tester.pumpWidget(scoped(_graph, app(JellyfinBrowser(
+        accounts: accounts, controller: controller, onSelect: (_) {}, onPutUp: (_) {}))));
     await settle(tester);
     expect(find.text('Fresh Show'), findsWidgets);
     expect(find.text('S1E1'), findsWidgets);
@@ -298,9 +303,9 @@ void main() {
     final accounts = JellyfinAccounts(
         store: MemoryJellyfinStore(), httpFactory: () => fake, deviceName: 'Test');
     await accounts.ensureLoaded(validate: false);
-    await tester.pumpWidget(app(SingleChildScrollView(
+    await tester.pumpWidget(scoped(_graph, app(SingleChildScrollView(
         child: JellyfinAccountsPanel(
-            accounts: accounts, pollInterval: const Duration(milliseconds: 100)))));
+            accounts: accounts, pollInterval: const Duration(milliseconds: 100))))));
     await tester.tap(find.byKey(const ValueKey('jf-add-server')));
     await tester.pump();
     await tester.enterText(find.byKey(const ValueKey('jf-address')), 'example.invalid');
@@ -351,8 +356,8 @@ void main() {
     await setSize(tester, const Size(1200, 900));
     final accounts = JellyfinAccounts(store: MemoryJellyfinStore(), httpFactory: () => FakeJellyfin());
     await accounts.ensureLoaded(validate: false);
-    await tester.pumpWidget(app(JellyfinPickerSource(
-        accounts: accounts, onSelect: (_) {}, onPutUp: (_) {}, onOpenIntegrations: () {})));
+    await tester.pumpWidget(scoped(_graph, app(JellyfinPickerSource(
+        accounts: accounts, onSelect: (_) {}, onPutUp: (_) {}, onOpenIntegrations: () {}))));
     await tester.pump();
     expect(find.byKey(const ValueKey('jf-sign-in')), findsOneWidget);
     expect(find.text('Open Integrations'), findsOneWidget);

apps/desktop/test/jellyfin_session_test.dart

@@ -21,6 +21,11 @@ import 'package:starsync/src/shell/library_tab.dart' show putUpJellyfinMedia;
 import 'jellyfin_accounts_test.dart';
 import 'jellyfin_browser_test.dart' show app, setSize, settle;
 
+import 'test_graph.dart';
+
+/// This file's composition root (see test_graph.dart).
+final _graph = testGraph();
+
 const episodeId = 'b18826be994070a79f9b52bc0f66f052'; // Black Summoner S1E6
 const nextEpisodeId = '74c50bdbf83e8fef231dd7710058e197'; // S1E7
 const seriesId = 'e9aec9c14a1fcab775111844112b4cf7';
@@ -485,7 +490,7 @@ void main() {
         SeriesRoute(const JellyfinItem(id: arifuretaId, name: 'Arifureta', type: 'Series'),
             seasonId: season2Id),
       ]));
-      await tester.pumpWidget(app(JellyfinBrowser(accounts: accounts, onSelect: (_) {}, onPutUp: (_) {})));
+      await tester.pumpWidget(scoped(_graph, app(JellyfinBrowser(accounts: accounts, onSelect: (_) {}, onPutUp: (_) {}))));
       await settle(tester);
       final s2 = tester.widget<ChoiceChip>(find.byKey(const ValueKey('season-$season2Id')));
       expect(s2.selected, isTrue);
@@ -506,18 +511,18 @@ void main() {
 
     testWidgets('end card: Next prompt, countdown with Cancel', (tester) async {
       var play = 0, cancel = 0;
-      await tester.pumpWidget(app(EndOfEpisodeCard(
-          next: next, countdown: null, onPlayNow: () => play++, onCancel: () => cancel++)));
+      await tester.pumpWidget(scoped(_graph, app(EndOfEpisodeCard(
+          next: next, countdown: null, onPlayNow: () => play++, onCancel: () => cancel++))));
       expect(find.text('Next: S1E7 Battle with the Heroes'), findsOneWidget);
       expect(find.byKey(const ValueKey('auto-advance-cancel')), findsNothing);
       await tester.tap(find.byKey(const ValueKey('play-next')));
       expect(play, 1);
 
-      await tester.pumpWidget(app(EndOfEpisodeCard(
+      await tester.pumpWidget(scoped(_graph, app(EndOfEpisodeCard(
           next: next,
           countdown: AutoAdvance(mediaId: 3, secondsLeft: 7, next: next, swapper: false),
           onPlayNow: () => play++,
-          onCancel: () => cancel++)));
+          onCancel: () => cancel++))));
       expect(find.text('Next episode in 7 s'), findsOneWidget);
       await tester.tap(find.byKey(const ValueKey('auto-advance-cancel')));
       expect(cancel, 1);
@@ -525,7 +530,7 @@ void main() {
 
     testWidgets('next-episode pill: faint at rest, lit on hover, click puts it up', (tester) async {
       var pressed = 0;
-      await tester.pumpWidget(app(Align(child: NextEpisodePill(episode: next, onPressed: () => pressed++))));
+      await tester.pumpWidget(scoped(_graph, app(Align(child: NextEpisodePill(episode: next, onPressed: () => pressed++)))));
       double opacity() => tester.widget<AnimatedOpacity>(find.descendant(
           of: find.byType(NextEpisodePill), matching: find.byType(AnimatedOpacity))).opacity;
       expect(opacity(), lessThan(0.5));
@@ -541,10 +546,10 @@ void main() {
 
     testWidgets('blocked card offers to link an account', (tester) async {
       var link = 0;
-      await tester.pumpWidget(app(JellyfinBlockedCard(
+      await tester.pumpWidget(scoped(_graph, app(JellyfinBlockedCard(
           blocked: const BlockedPlay(serverId: fixtureServerId, serverName: 'Example Server'),
           onLinkAccount: () => link++,
-          onRetry: () {})));
+          onRetry: () {}))));
       expect(find.text('No Jellyfin account here for Example Server, and nobody is passing it on'),
           findsOneWidget);
       await tester.tap(find.byKey(const ValueKey('link-jellyfin-account')));

apps/desktop/test/library_rows_test.dart

@@ -226,7 +226,7 @@ void main() {
       final refused = await previewLink('https://cdn.example/b.mp4',
           probe: (url) async => LinkProbe.page(Uri.parse(url), ytDlpError: 'odd', status: 403));
       expect((refused!.title, refused.problem), ('b.mp4', 'Not allowed (403)'));
-      expect(await previewLink('not a link'), isNull);
+      expect(await previewLink('not a link', probe: (url) async => throw StateError('no probe')), isNull);
     });
 
     test('ago text', () {

apps/desktop/test/library_tab_test.dart

@@ -1,5 +1,3 @@
-// restructure: rewrite in step 3 (Your server): the "solo" and "hosting"
-// tests (D9: no solo mode); the rest stays.
 import 'dart:convert';
 
 import 'package:flutter/material.dart';
@@ -16,6 +14,11 @@ import 'jellyfin_accounts_test.dart'
     show FakeJellyfin, arifuretaId, fixtureServerId, jellyfinFixture, linkedAccounts, season2Id;
 import 'jellyfin_browser_test.dart' show fixtureNow, settle;
 
+import 'test_graph.dart';
+
+/// This file's composition root (see test_graph.dart).
+final _graph = testGraph();
+
 const bsSeries = 'e9aec9c14a1fcab775111844112b4cf7';
 const bsEpisode = 'b18826be994070a79f9b52bc0f66f052';
 const bsSeason = 'fb0b77cfda15445f9319ed9d753dba23';
@@ -50,13 +53,13 @@ FakeJellyfin libraryFake() {
 }
 
 class FilesStub extends StatelessWidget {
-  final bool solo, relayed;
+  final bool alone, relayed;
   final Future<String?> Function(String path) onPlay;
-  const FilesStub({super.key, required this.solo, required this.relayed, required this.onPlay});
+  const FilesStub({super.key, required this.alone, required this.relayed, required this.onPlay});
 
   @override
   Widget build(BuildContext context) => Column(children: [
-        Text('files solo=$solo relayed=$relayed'),
+        Text('files alone=$alone relayed=$relayed'),
         TextButton(
           key: const ValueKey('stub-play'),
           onPressed: () => onPlay('/v/a.mkv'),
@@ -77,7 +80,7 @@ class Harness {
 Future<Harness> pumpLibrary(
   WidgetTester tester,
   Size size, {
-  bool solo = false,
+  bool alone = false,
   bool isHost = false,
   MediaKind source = MediaKind.jellyfin,
   Harness? reuse,
@@ -97,7 +100,7 @@ Future<Harness> pumpLibrary(
     addTearDown(c.dispose);
     h = Harness(c, accounts, fake);
   }
-  await tester.pumpWidget(MaterialApp(
+  await tester.pumpWidget(scoped(_graph, MaterialApp(
     theme: ThemeData.dark(),
     home: Scaffold(
       body: LibraryTab(
@@ -105,7 +108,7 @@ Future<Harness> pumpLibrary(
         key: UniqueKey(),
         controller: h.controller,
         accounts: h.accounts,
-        solo: solo,
+        alone: alone,
         isHost: isHost,
         jellyfinStart: start,
         recentLinks: h.recents,
@@ -115,15 +118,15 @@ Future<Harness> pumpLibrary(
             : url.contains('bilibili')
                 ? LinkProbe.page(Uri.parse(url), ytDlpError: 'HTTP Error 412: Precondition Failed')
                 : LinkProbe.page(Uri.parse(url), info: const YtDlpInfo(title: 'A video', uploader: 'Chan')),
-        filesBuilder: (context, {required solo, required relayed, required onPlay, nowPlayingPath}) =>
-            FilesStub(solo: solo, relayed: relayed, onPlay: onPlay),
+        filesBuilder: (context, {required alone, required relayed, required onPlay, nowPlayingPath}) =>
+            FilesStub(alone: alone, relayed: relayed, onPlay: onPlay),
         onPutUp: (m) async {
           h.put.add(m);
           return null;
         },
       ),
     ),
-  ));
+  )));
   await settle(tester, 10);
   return h;
 }
@@ -156,7 +159,7 @@ void main() {
 
     await tester.tap(find.text('Files'));
     await settle(tester, 10);
-    expect(find.text('files solo=false relayed=true'), findsOneWidget);
+    expect(find.text('files alone=false relayed=true'), findsOneWidget);
     await tester.tap(find.byKey(const ValueKey('stub-play')));
     await settle(tester);
     expect(h.put, [const FileMedia('/v/a.mkv')]);
@@ -251,8 +254,8 @@ void main() {
     expect(tester.takeException(), isNull);
   });
 
-  testWidgets('solo: buttons say Play and put up; a link goes direct, no relay modes', (tester) async {
-    final h = await pumpLibrary(tester, const Size(1600, 1000), solo: true);
+  testWidgets('nobody else in the server (D9): buttons say Play and put up; a link goes direct, no relay modes', (tester) async {
+    final h = await pumpLibrary(tester, const Size(1600, 1000), alone: true);
     await tester.tap(arifuretaCard());
     await settle(tester, 10);
     final go = find.byKey(const ValueKey('details-put-up'));
@@ -267,7 +270,7 @@ void main() {
     await tester.enterText(find.byKey(const ValueKey('link-field')), 'https://cdn.example/a.mkv');
     await settle(tester, 10);
     expect(find.text('How the others get it'), findsNothing);
-    expect(find.text(soloPlayHint), findsOneWidget);
+    expect(find.text(alonePlayHint), findsOneWidget);
     await tester.tap(find.byKey(const ValueKey('link-put-up')));
     await settle(tester, 10);
     expect(h.put.last, const LinkMedia('https://cdn.example/a.mkv'));
@@ -324,9 +327,9 @@ void main() {
     expect(tester.takeException(), isNull);
   });
 
-  testWidgets('hosting: files stream from here; now-playing file passes through', (tester) async {
+  testWidgets('your server: files stream from here; now-playing file passes through', (tester) async {
     await pumpLibrary(tester, const Size(1400, 900), source: MediaKind.file, isHost: true);
-    expect(find.text('files solo=false relayed=false'), findsOneWidget);
+    expect(find.text('files alone=false relayed=false'), findsOneWidget);
   });
 
   testWidgets('the last pick comes back selected; "Change video" opens on its series', (tester) async {
@@ -344,7 +347,7 @@ void main() {
     expect(c.selected!.itemId, bsEpisode);
     expect(c.source, MediaKind.jellyfin);
     final h = Harness(c, accounts, FakeJellyfin());
-    await pumpLibrary(tester, const Size(1600, 1000), reuse: h, solo: true);
+    await pumpLibrary(tester, const Size(1600, 1000), reuse: h, alone: true);
     expect(find.byKey(const ValueKey('jf-details')), findsOneWidget);
     expect(find.text('Black Summoner'), findsWidgets);
 

apps/desktop/test/minimal_controls_test.dart

@@ -12,6 +12,11 @@ import 'package:starsync/src/state/settings.dart';
 import 'package:starsync/src/update/update_controller.dart';
 import 'package:starsync/src/widgets/app_menu.dart';
 
+import 'test_graph.dart';
+
+/// This file's composition root (see test_graph.dart).
+final _graph = testGraph();
+
 // The Minimal skin's pieces and the shared controls frame (never the
 // session screen or a media_kit `Video`).
 
@@ -81,8 +86,8 @@ void main() {
 
   group('timeline', () {
     testWidgets('played part, elapsed left, remaining right, cache label', (tester) async {
-      await tester.pumpWidget(host(MinimalTimeline(
-          position: m(6), duration: m(24), buffered: m(6, 30), chapters: chapters, onSeek: (_) {})));
+      await tester.pumpWidget(scoped(_graph, host(MinimalTimeline(
+          position: m(6), duration: m(24), buffered: m(6, 30), chapters: chapters, onSeek: (_) {}))));
       final bar = tester.getRect(find.byKey(const ValueKey('minimal-timeline')));
       expect(bar.width, 800);
       expect(bar.height, MinimalTimelineSpec.size);
@@ -98,16 +103,16 @@ void main() {
     });
 
     testWidgets('the total instead of the time left', (tester) async {
-      await tester.pumpWidget(host(MinimalTimeline(
-          position: m(6), duration: m(24), remaining: false, onSeek: (_) {})));
+      await tester.pumpWidget(scoped(_graph, host(MinimalTimeline(
+          position: m(6), duration: m(24), remaining: false, onSeek: (_) {}))));
       expect(painter(tester).right, '24:00');
     });
 
     testWidgets('a press on the right-hand time switches it, no seek', (tester) async {
       final seeks = <Duration>[];
       var toggled = 0;
-      await tester.pumpWidget(host(MinimalTimeline(
-          position: m(6), duration: m(24), onSeek: seeks.add, onToggleTime: () => toggled++)));
+      await tester.pumpWidget(scoped(_graph, host(MinimalTimeline(
+          position: m(6), duration: m(24), onSeek: seeks.add, onToggleTime: () => toggled++))));
       final bar = tester.getRect(find.byKey(const ValueKey('minimal-timeline')));
       await tester.tapAt(Offset(bar.right - 20, bar.center.dy));
       expect(toggled, 1);
@@ -115,12 +120,12 @@ void main() {
     });
 
     testWidgets('a mark at each chapter start', (tester) async {
-      await tester.pumpWidget(host(MinimalTimeline(position: m(1), duration: m(24), chapters: chapters, onSeek: (_) {})));
+      await tester.pumpWidget(scoped(_graph, host(MinimalTimeline(position: m(1), duration: m(24), chapters: chapters, onSeek: (_) {}))));
       expect(painter(tester).chapters, [for (final c in chapters) c.start.inSeconds / m(24).inSeconds]);
     });
 
     testWidgets('hover: chapter title over the time, above the band', (tester) async {
-      await tester.pumpWidget(host(MinimalTimeline(position: m(1), duration: m(24), chapters: chapters, onSeek: (_) {})));
+      await tester.pumpWidget(scoped(_graph, host(MinimalTimeline(position: m(1), duration: m(24), chapters: chapters, onSeek: (_) {}))));
       final bar = tester.getRect(find.byKey(const ValueKey('minimal-timeline')));
       final mouse = await mouseAt(tester, Offset.zero);
       // 1:51 of 24:00: inside "Opening".
@@ -143,7 +148,7 @@ void main() {
 
     testWidgets('a press on a hovered chapter mark jumps to its chapter', (tester) async {
       final seeks = <Duration>[];
-      await tester.pumpWidget(host(MinimalTimeline(position: m(1), duration: m(24), chapters: chapters, onSeek: seeks.add)));
+      await tester.pumpWidget(scoped(_graph, host(MinimalTimeline(position: m(1), duration: m(24), chapters: chapters, onSeek: seeks.add))));
       final bar = tester.getRect(find.byKey(const ValueKey('minimal-timeline')));
       final at = Offset(bar.left + bar.width * 2 / 24 + 3, bar.top + 2);
       final mouse = await mouseAt(tester, at);
@@ -159,8 +164,8 @@ void main() {
 
     testWidgets('hidden controls: the progress line, no text, no input', (tester) async {
       final seeks = <Duration>[];
-      await tester.pumpWidget(host(MinimalTimeline(
-          position: m(12), duration: m(24), buffered: m(14), chapters: chapters, expanded: false, onSeek: seeks.add)));
+      await tester.pumpWidget(scoped(_graph, host(MinimalTimeline(
+          position: m(12), duration: m(24), buffered: m(14), chapters: chapters, expanded: false, onSeek: seeks.add))));
       final bar = tester.getRect(find.byKey(const ValueKey('minimal-timeline')));
       expect(bar.height, MinimalTimeline.collapsedHeight);
       final p = painter(tester);
@@ -177,7 +182,7 @@ void main() {
 
     testWidgets('press seeks, every drag move seeks, release holds the target', (tester) async {
       final seeks = <Duration>[];
-      await tester.pumpWidget(host(MinimalTimeline(position: m(1), duration: m(24), chapters: chapters, onSeek: seeks.add)));
+      await tester.pumpWidget(scoped(_graph, host(MinimalTimeline(position: m(1), duration: m(24), chapters: chapters, onSeek: seeks.add))));
       final bar = tester.getRect(find.byKey(const ValueKey('minimal-timeline')));
       final g0 = await tester.startGesture(Offset(bar.left + bar.width / 4, bar.center.dy), kind: PointerDeviceKind.mouse);
       expect(seeks, [m(6)], reason: 'the press seeks');
@@ -220,7 +225,7 @@ void main() {
     bool up(WidgetTester tester) => tester.state<ControlsFrameState>(find.byType(ControlsFrame)).visible;
 
     testWidgets('hide after the delay, mouse brings them back', (tester) async {
-      await tester.pumpWidget(frame());
+      await tester.pumpWidget(scoped(_graph, frame()));
       expect(up(tester), isTrue);
       await tester.pump(const Duration(seconds: 4));
       await tester.pumpAndSettle();
@@ -237,7 +242,7 @@ void main() {
     });
 
     testWidgets('a long drag on the timeline keeps the controls up', (tester) async {
-      await tester.pumpWidget(frame());
+      await tester.pumpWidget(scoped(_graph, frame()));
       final bar = tester.getRect(find.byKey(const ValueKey('minimal-timeline')));
       final g = await tester.startGesture(Offset(bar.left + 100, bar.center.dy), kind: PointerDeviceKind.mouse);
       for (var i = 0; i < 10; i++) {
@@ -254,7 +259,7 @@ void main() {
     });
 
     testWidgets('an open app menu keeps the controls up', (tester) async {
-      await tester.pumpWidget(frame(
+      await tester.pumpWidget(scoped(_graph, frame(
         child: Builder(
           builder: (context) => TextButton(
             key: const ValueKey('open'),
@@ -262,7 +267,7 @@ void main() {
             child: const Text('open'),
           ),
         ),
-      ));
+      )));
       await tester.tap(find.byKey(const ValueKey('open')));
       await tester.pumpAndSettle();
       expect(find.text('One'), findsOneWidget);
@@ -277,13 +282,13 @@ void main() {
 
     testWidgets('double-click on the picture, not on the bars', (tester) async {
       var doubles = 0;
-      await tester.pumpWidget(MaterialApp(
+      await tester.pumpWidget(scoped(_graph, MaterialApp(
         home: ControlsFrame(
           onDoubleClick: () => doubles++,
           barBottom: 100,
           builder: (context, visible) => const SizedBox.expand(),
         ),
-      ));
+      )));
       Future<void> twice(Offset at) async {
         await tester.tapAt(at, kind: PointerDeviceKind.mouse);
         await tester.pump(const Duration(milliseconds: 100));
@@ -300,10 +305,10 @@ void main() {
 
   group('buttons', () {
     testWidgets('count badge in the accent; tooltip on the app glass', (tester) async {
-      await tester.pumpWidget(host(const Row(children: [
+      await tester.pumpWidget(scoped(_graph, host(const Row(children: [
         MinimalButton(key: ValueKey('subs'), icon: Icons.subtitles_outlined, tooltip: 'Subtitles', badge: 2, onPressed: null),
         MinimalButton(key: ValueKey('plain'), icon: Icons.menu, tooltip: 'Menu', onPressed: null),
-      ])));
+      ]))));
       expect(
           find.descendant(of: find.byKey(const ValueKey('subs')), matching: find.byKey(const ValueKey('minimal-badge'))),
           findsOneWidget);
@@ -320,7 +325,7 @@ void main() {
       final got = <double>[];
       var volume = 80.0;
       var before = 80.0;
-      await tester.pumpWidget(host(StatefulBuilder(
+      await tester.pumpWidget(scoped(_graph, host(StatefulBuilder(
         builder: (context, setState) => Row(children: [
           VolumeControl(
             volume: volume,
@@ -337,7 +342,7 @@ void main() {
                 MinimalButton(key: const ValueKey('speaker'), icon: icon, tooltip: tip, onPressed: onPressed),
           ),
         ]),
-      )));
+      ))));
       await tester.tap(find.byKey(const ValueKey('speaker')));
       await tester.pump();
       await tester.tap(find.byKey(const ValueKey('speaker')));
@@ -361,7 +366,7 @@ void main() {
       final steps = <int>[];
       final list = ScrollController();
       addTearDown(list.dispose);
-      await tester.pumpWidget(MaterialApp(
+      await tester.pumpWidget(scoped(_graph, MaterialApp(
         home: VolumeWheel(
           onStep: steps.add,
           child: Stack(children: [
@@ -375,7 +380,7 @@ void main() {
             ),
           ]),
         ),
-      ));
+      )));
       Future<void> wheel(Offset at, Offset delta) =>
           tester.sendEventToBinding(PointerScrollEvent(kind: PointerDeviceKind.mouse, position: at, scrollDelta: delta));
       await wheel(const Offset(100, 400), const Offset(0, -60));
@@ -407,7 +412,7 @@ void main() {
     tester.view.physicalSize = const Size(1280, 2400);
     tester.view.devicePixelRatio = 1;
     addTearDown(tester.view.reset);
-    await tester.pumpWidget(MaterialApp(
+    await tester.pumpWidget(scoped(_graph, MaterialApp(
       theme: ThemeData.dark(),
       home: Scaffold(
         body: SettingsTab(
@@ -416,7 +421,7 @@ void main() {
           updates: UpdateController(currentVersion: '0.0.0-dev'),
         ),
       ),
-    ));
+    )));
     final design = find.byKey(const ValueKey('player-design'));
     expect(find.text('Player design'), findsOneWidget);
     expect(tester.widget<AppSelect<ControlsSkin>>(design).value, ControlsSkin.standard);

apps/desktop/test/player_controls_test.dart

@@ -8,6 +8,11 @@ import 'package:starsync/src/jellyfin/track_prefs.dart';
 import 'package:starsync/src/playback/media_marks.dart';
 import 'package:starsync/src/screens/session/player_controls.dart';
 
+import 'test_graph.dart';
+
+/// This file's composition root (see test_graph.dart).
+final _graph = testGraph();
+
 // The control-bar pieces alone (never the session screen or a `Video`):
 // the Standard seek bar, the skip pill and the shared track / chapter
 // lists.
@@ -38,8 +43,8 @@ Widget host(Widget child, {double width = 960}) => MaterialApp(
 void main() {
   group('seek bar', () {
     testWidgets('a mark at each chapter start but the first, placed by time', (tester) async {
-      await tester.pumpWidget(host(ChapterSeekBar(
-          position: m(1), duration: m(24), chapters: chapters, onSeek: (_) {})));
+      await tester.pumpWidget(scoped(_graph, host(ChapterSeekBar(
+          position: m(1), duration: m(24), chapters: chapters, onSeek: (_) {}))));
       expect(find.byKey(const ValueKey('chapter-mark-0')), findsNothing, reason: 'starts at 0');
       final bar = tester.getRect(find.byKey(const ValueKey('seek-bar')));
       for (final c in chapters.skip(1)) {
@@ -51,16 +56,16 @@ void main() {
     });
 
     testWidgets('no marks without a duration or chapters', (tester) async {
-      await tester.pumpWidget(host(ChapterSeekBar(
-          position: Duration.zero, duration: Duration.zero, chapters: chapters, onSeek: (_) {})));
+      await tester.pumpWidget(scoped(_graph, host(ChapterSeekBar(
+          position: Duration.zero, duration: Duration.zero, chapters: chapters, onSeek: (_) {}))));
       expect(find.byKey(const ValueKey('chapter-mark-1')), findsNothing);
-      await tester.pumpWidget(host(ChapterSeekBar(position: Duration.zero, duration: m(24), onSeek: (_) {})));
+      await tester.pumpWidget(scoped(_graph, host(ChapterSeekBar(position: Duration.zero, duration: m(24), onSeek: (_) {}))));
       expect(find.byKey(const ValueKey('chapter-mark-1')), findsNothing);
     });
 
     testWidgets('hover shows the chapter title above the time', (tester) async {
-      await tester.pumpWidget(host(ChapterSeekBar(
-          position: m(1), duration: m(24), chapters: chapters, onSeek: (_) {})));
+      await tester.pumpWidget(scoped(_graph, host(ChapterSeekBar(
+          position: m(1), duration: m(24), chapters: chapters, onSeek: (_) {}))));
       final bar = tester.getRect(find.byKey(const ValueKey('seek-bar')));
       final mouse = await tester.createGesture(kind: PointerDeviceKind.mouse);
       await mouse.addPointer(location: Offset.zero);
@@ -84,7 +89,7 @@ void main() {
     });
 
     testWidgets('no chapters: the hover shows only the time', (tester) async {
-      await tester.pumpWidget(host(ChapterSeekBar(position: m(1), duration: m(24), onSeek: (_) {})));
+      await tester.pumpWidget(scoped(_graph, host(ChapterSeekBar(position: m(1), duration: m(24), onSeek: (_) {}))));
       final bar = tester.getRect(find.byKey(const ValueKey('seek-bar')));
       final mouse = await tester.createGesture(kind: PointerDeviceKind.mouse);
       await mouse.addPointer(location: Offset.zero);
@@ -97,8 +102,8 @@ void main() {
 
     testWidgets('drag seeks on every move and on release', (tester) async {
       final seeks = <Duration>[];
-      await tester.pumpWidget(host(ChapterSeekBar(
-          position: m(1), duration: m(24), chapters: chapters, onSeek: seeks.add)));
+      await tester.pumpWidget(scoped(_graph, host(ChapterSeekBar(
+          position: m(1), duration: m(24), chapters: chapters, onSeek: seeks.add))));
       final bar = tester.getRect(find.byKey(const ValueKey('seek-bar')));
       final g = await tester.startGesture(Offset(bar.left + bar.width / 4, bar.center.dy),
           kind: PointerDeviceKind.mouse);
@@ -120,7 +125,7 @@ void main() {
         (SkipKind.ending, 'Skip ED'),
         (SkipKind.fixed, 'Skip 1:30'),
       ]) {
-        await tester.pumpWidget(host(Align(child: SkipPill(offer: SkipOffer(kind, m(2)), onPressed: () => pressed++))));
+        await tester.pumpWidget(scoped(_graph, host(Align(child: SkipPill(offer: SkipOffer(kind, m(2)), onPressed: () => pressed++)))));
         expect(find.text(label), findsOneWidget);
       }
       double opacity() => tester.widget<AnimatedOpacity>(

apps/desktop/test/player_settings_test.dart

@@ -1,5 +1,3 @@
-// restructure: rewrite in step 3 (Your server): invite addresses (P24) and
-// the hosting invite; the settings cards stay.
 import 'dart:io';
 
 import 'package:flutter/material.dart';
@@ -15,10 +13,18 @@ import 'package:starsync/src/shaders/shader_presets.dart';
 import 'package:starsync/src/shell/avatar.dart';
 import 'package:starsync/src/shell/party_strip.dart';
 import 'package:starsync/src/shell/settings_tab.dart';
-import 'package:starsync/src/state/session_state.dart';
 import 'package:starsync/src/state/settings.dart';
 import 'package:starsync/src/update/update_controller.dart';
 
+import 'package:starsync/src/session/invite.dart';
+import 'package:starsync/src/session/navigation.dart' show Place;
+import 'package:starsync/src/state/connect_prefs.dart' show RecentServer;
+
+import 'test_graph.dart';
+
+/// This file's composition root (see test_graph.dart).
+final _graph = testGraph();
+
 // The player settings card (both skins, never a media_kit `Video`), the
 // Settings pages, the host flag in the party UI and invite addresses.
 
@@ -39,7 +45,7 @@ Future<void> pick(WidgetTester tester, String key, String item) async {
 
 void main() {
   final s = AppSettings.instance;
-  final coord = SessionState.instance.coordinator;
+  final coord = _graph.coordinator;
 
   tearDown(() {
     s.controlsSkin.value = ControlsSkin.standard;
@@ -54,8 +60,8 @@ void main() {
     coord.playback.tracks.value = const [];
     coord.serverState.value = null;
     coord.hostFile = null;
-    SessionState.instance.route.value = AppRoute.home;
-    SessionState.instance.recents.value = const [];
+    _graph.navigation.place.value = Place.none;
+    _graph.forms.recents.value = const [];
   });
 
   Widget opener() => Builder(
@@ -73,7 +79,7 @@ void main() {
         MpvTrack(id: 1, type: JellyfinStreamType.audio, language: 'jpn', codec: 'eac3', channels: 2, selected: true),
         MpvTrack(id: 1, type: JellyfinStreamType.subtitle, language: 'eng', codec: 'ass', title: 'Full'),
       ];
-      await tester.pumpWidget(app(Align(alignment: Alignment.bottomRight, child: opener())));
+      await tester.pumpWidget(scoped(_graph, app(Align(alignment: Alignment.bottomRight, child: opener()))));
       await tester.tap(find.byKey(const ValueKey('open-settings')));
       await tester.pumpAndSettle();
       final card = find.byKey(const ValueKey('player-settings-card'));
@@ -113,10 +119,10 @@ void main() {
 
     testWidgets('keeps the controls up while open', (tester) async {
       bigWindow(tester);
-      await tester.pumpWidget(app(ControlsFrame(
+      await tester.pumpWidget(scoped(_graph, app(ControlsFrame(
         hideAfter: const Duration(seconds: 1),
         builder: (context, visible) => Align(alignment: Alignment.bottomRight, child: opener()),
-      )));
+      ))));
       final controls = tester.state<ControlsFrameState>(find.byType(ControlsFrame));
       await tester.tap(find.byKey(const ValueKey('open-settings')));
       await tester.pumpAndSettle();
@@ -135,12 +141,12 @@ void main() {
     Future<void> pumpSettings(WidgetTester tester, SettingsSection section,
         {Future<AnimeFlowMe> Function()? me, Size size = const Size(1280, 1400)}) async {
       bigWindow(tester, size);
-      await tester.pumpWidget(app(SettingsTab(
+      await tester.pumpWidget(scoped(_graph, app(SettingsTab(
         section: section,
         onSection: (_) {},
         updates: UpdateController(currentVersion: '0.0.0-dev'),
         animeFlowMe: me ?? () async => throw const AnimeFlowException(401, AnimeFlowErrorCode.missingToken, 'x'),
-      )));
+      ))));
       await tester.pumpAndSettle();
     }
 
@@ -196,26 +202,27 @@ void main() {
       expect(s.hiddenControls.value, isEmpty);
     });
 
-    testWidgets('Party & network: host defaults and recent servers with remove', (tester) async {
-      SessionState.instance.recents.value = const [
-        RecentServer(hosted: false, host: 'vps.example', port: '8080', secret: 'pw'),
-        RecentServer(hosted: true, host: '127.0.0.1', port: '9000'),
+    testWidgets('Party & network: your server\'s port and password, recent servers with remove', (tester) async {
+      _graph.forms.recents.value = const [
+        RecentServer(host: 'vps.example', port: '8080', secret: 'pw'),
+        RecentServer(host: 'friend.example', port: '9000'),
       ];
       await pumpSettings(tester, SettingsSection.network);
-      expect(find.text('Default port'), findsOneWidget);
+      expect(find.text('Your server'), findsOneWidget);
+      expect(find.text('Port'), findsOneWidget);
       expect(find.text('vps.example:8080'), findsOneWidget);
-      expect(find.text('Hosted on port 9000'), findsOneWidget);
+      expect(find.text('friend.example:9000'), findsOneWidget);
       await tester.enterText(find.byKey(const ValueKey('host-port')), '70000');
       await tester.pump();
       expect(find.text('A number from 1 to 65535'), findsOneWidget);
       await tester.enterText(find.byKey(const ValueKey('host-port')), '9100');
       await tester.pump();
-      expect(SessionState.instance.lastForm.hostPort, '9100');
+      expect(_graph.forms.form.hostPort, '9100');
       await tester.tap(find.descendant(
           of: find.byKey(const ValueKey('recent-vps.example:8080')), matching: find.byTooltip('Remove')));
       await tester.pumpAndSettle();
       expect(find.text('vps.example:8080'), findsNothing);
-      SessionState.instance.lastForm.hostPort = '8080';
+      _graph.forms.form.hostPort = '8080';
     });
 
     testWidgets('Integrations: AnimeFlow says who you are connected as, or why not', (tester) async {
@@ -224,7 +231,7 @@ void main() {
               userId: 'u1', name: 'foxyz', scopes: {AnimeFlowScope.view, AnimeFlowScope.request}));
       expect(find.text('connected as foxyz · can view, request'), findsOneWidget);
       // A fresh tree: the card keeps its first answer otherwise.
-      await tester.pumpWidget(const SizedBox());
+      await tester.pumpWidget(scoped(_graph, const SizedBox()));
       await pumpSettings(tester, SettingsSection.integrations,
           me: () async => throw const AnimeFlowException(
               401, AnimeFlowErrorCode.missingToken, 'No linked Jellyfin account for AnimeFlow'));
@@ -239,23 +246,43 @@ void main() {
       final chip = tester.widget<ChoiceChip>(find.byKey(const ValueKey('settings-network')));
       expect(chip.selected, isTrue);
       expect((chip.avatar! as Icon).icon, Icons.hub_outlined);
-      expect(find.text('Default port'), findsOneWidget);
+      expect(find.text('Port'), findsOneWidget);
     });
   });
 
   group('party', () {
-    test('invite addresses: LAN IPv4 with the port, private first, no loopback', () {
+    test('invite addresses: home network first; no proxy fake-IP, link-local, loopback or container bridge', () {
+      ({String name, InternetAddress address}) at(String name, String ip) => (name: name, address: InternetAddress(ip));
       final list = inviteAddresses([
-        InternetAddress('127.0.0.1'),
-        InternetAddress('100.64.1.2'),
-        InternetAddress('192.168.1.20'),
-        InternetAddress('169.254.3.4'),
-        InternetAddress('::1'),
-        InternetAddress('10.0.0.5'),
-        InternetAddress('192.168.1.20'),
-      ], '8080');
-      expect(list, ['192.168.1.20:8080', '10.0.0.5:8080', '100.64.1.2:8080']);
-      expect(inviteAddresses(const [], '8080'), isEmpty);
+        at('lo', '127.0.0.1'),
+        at('Meta', '198.18.0.1'), // a TUN proxy's fake-IP range (198.18.0.0/15)
+        at('utun', '198.19.255.2'),
+        at('tailscale0', '100.64.1.2'),
+        at('docker0', '172.17.0.1'),
+        at('br-3f2a', '172.18.0.1'),
+        at('virbr0', '192.168.122.1'),
+        at('eth1', '10.0.0.5'),
+        at('wlan0', '169.254.3.4'),
+        at('eth0', '192.168.1.20'),
+        at('eth0', '192.168.1.20'),
+        at('eth0', '::1'),
+        at('wan', '203.0.113.7'),
+      ]);
+      expect(list, ['192.168.1.20', '10.0.0.5', '100.64.1.2', '203.0.113.7']);
+      expect(inviteAddresses(const []), isEmpty);
+      expect(isFakeIp(InternetAddress('198.19.1.1').rawAddress), isTrue);
+      expect(isFakeIp(InternetAddress('198.20.1.1').rawAddress), isFalse);
+    });
+
+    test('an invite: the address, whether to ask for a password, the version; pasted back', () {
+      const invite = Invite(host: '192.168.1.20', port: 8080, password: true, version: '1.3.0');
+      expect(invite.address, '192.168.1.20:8080');
+      expect(invite.text, 'Join me on Starsync: 192.168.1.20:8080 (ask me for the password) · Starsync 1.3.0');
+      expect(invite.fp, isNull, reason: 'reserved for pinned certificates');
+      expect(addressIn(invite.text), (host: '192.168.1.20', port: '8080'));
+      expect(addressIn('vps.example.com:9000'), (host: 'vps.example.com', port: '9000'));
+      expect(addressIn('[fe80::1]:8080'), (host: 'fe80::1', port: '8080'));
+      expect(addressIn('just a host'), isNull);
     });
 
     void online(List<MemberView> members) {
@@ -267,7 +294,7 @@ void main() {
         mediaId: 0,
         members: members,
       );
-      SessionState.instance.route.value = AppRoute.session;
+      _graph.navigation.place.value = Place.friend;
     }
 
     testWidgets('the state\'s host flag crowns that member for everyone', (tester) async {
@@ -279,7 +306,7 @@ void main() {
       expect(avatars['Hana']!.host, isTrue);
       expect(avatars['Bob']!.host, isFalse);
       bigWindow(tester);
-      await tester.pumpWidget(app(const Center(child: MembersCard())));
+      await tester.pumpWidget(scoped(_graph, app(const Center(child: MembersCard()))));
       await tester.pumpAndSettle();
       expect(find.descendant(of: find.byKey(const ValueKey('member-m1')), matching: find.text('host')),
           findsOneWidget);
@@ -291,18 +318,28 @@ void main() {
       expect(find.text('Sit out'), findsOneWidget);
     });
 
-    testWidgets('hosting: Copy invite address lists this machine\'s addresses', (tester) async {
+    testWidgets('your server, not shared: only you, Invite; shared: the invite and Stop sharing', (tester) async {
       online(const [MemberView(id: 'm1', name: 'Me', ready: false, inSet: false, buffered: 0)]);
-      coord.hostFile = (_) async => null;
-      SessionState.instance.lastForm.hostPort = '8080';
+      _graph.navigation.place.value = Place.yours;
+      final yours = _graph.yourServer;
+      yours.port.value = 40000; // as if it runs
+      addTearDown(() {
+        yours.port.value = null;
+        yours.shared.value = null;
+      });
       bigWindow(tester);
-      await tester.pumpWidget(app(Center(
-        child: MembersCard(lanAddresses: (port) async => ['192.168.1.20:$port', '10.0.0.5:$port']),
-      )));
+      await tester.pumpWidget(scoped(_graph, app(const Center(child: MembersCard()))));
+      await tester.pumpAndSettle();
+      expect(find.text('Your server'), findsOneWidget);
+      expect(find.textContaining('Only you can reach it'), findsOneWidget);
+      expect(find.widgetWithText(TextButton, 'Invite'), findsOneWidget);
+      expect(find.byKey(const ValueKey('stop-sharing')), findsNothing);
+
+      yours.shared.value = const Invite(host: '192.168.1.20', port: 8080, version: '1.3.0');
       await tester.pumpAndSettle();
-      expect(find.text('Copy invite address'), findsOneWidget);
       expect(find.text('192.168.1.20:8080'), findsOneWidget);
-      expect(find.text('10.0.0.5:8080'), findsOneWidget);
+      expect(find.text('Copy invite'), findsOneWidget);
+      expect(find.byKey(const ValueKey('stop-sharing')), findsOneWidget);
       expect(find.textContaining('port 8080 forwarded'), findsOneWidget);
       expect(find.textContaining('VPS'), findsOneWidget);
     });

apps/desktop/test/player_status_test.dart

@@ -14,7 +14,11 @@ import 'package:starsync/src/session/now_playing.dart';
 import 'package:starsync/src/shell/now_playing_title.dart';
 import 'package:starsync/src/shell/session_player.dart';
 import 'package:starsync/src/shell/start_banner.dart';
-import 'package:starsync/src/state/session_state.dart';
+
+import 'test_graph.dart';
+
+/// This file's composition root (see test_graph.dart).
+final _graph = testGraph();
 
 // The one computed status (each input → text and level), the player's
 // title block, start card and status pill (never a media_kit `Video`).
@@ -78,7 +82,7 @@ StatusLine? line(StateBroadcast? state, {MemberView? self, ConnState conn = cons
     st(state, self: self, conn: conn, playerError: playerError).line;
 
 void main() {
-  final coord = SessionState.instance.coordinator;
+  final coord = _graph.coordinator;
 
   tearDown(() {
     debugArtBytes = null;
@@ -265,7 +269,7 @@ void main() {
     const now = NowPlaying(title: 'Frieren', episode: 'S1 E4 · The Land Where Souls Rest', posterHash: 'p');
 
     testWidgets('title, episode and a placeholder cover without art', (tester) async {
-      await tester.pumpWidget(host(const NowPlayingBlock(now: now)));
+      await tester.pumpWidget(scoped(_graph, host(const NowPlayingBlock(now: now))));
       expect(find.text('Frieren'), findsOneWidget);
       expect(find.text('S1 E4 · The Land Where Souls Rest'), findsOneWidget);
       expect(find.byIcon(Icons.movie_outlined), findsOneWidget);
@@ -276,16 +280,16 @@ void main() {
 
     testWidgets('the cover image once its bytes are here', (tester) async {
       debugArtBytes = (hash) => hash == 'p' ? png : null;
-      await tester.pumpWidget(host(const NowPlayingBlock(now: now)));
+      await tester.pumpWidget(scoped(_graph, host(const NowPlayingBlock(now: now))));
       final image = tester.widget<Image>(find.byType(Image));
       expect((image.image as MemoryImage).bytes, png);
       expect(image.gaplessPlayback, isTrue);
     });
 
     testWidgets('no cover, no episode: just the title; long titles ellipsize', (tester) async {
-      await tester.pumpWidget(host(
+      await tester.pumpWidget(scoped(_graph, host(
           NowPlayingBlock(now: NowPlaying(title: 'A very long title ' * 10), cover: false, compact: true),
-          width: 200));
+          width: 200)));
       expect(find.byType(ArtCover), findsNothing);
       expect(find.byKey(const ValueKey('now-playing-episode')), findsNothing);
       expect(tester.takeException(), isNull);
@@ -293,7 +297,7 @@ void main() {
   });
 
   testWidgets('start banner: up before playback, fades on play, never back for that media', (tester) async {
-    await tester.pumpWidget(const MaterialApp(home: SizedBox(width: 1280, height: 720, child: StartBanner())));
+    await tester.pumpWidget(scoped(_graph, const MaterialApp(home: SizedBox(width: 1280, height: 720, child: StartBanner()))));
     final card = find.byKey(const ValueKey('start-card-title'));
     expect(card, findsNothing);
     coord.serverState.value = held([mv('a', 'Alex')]);
@@ -332,7 +336,7 @@ void main() {
       tester.view.physicalSize = size;
       tester.view.devicePixelRatio = 1;
       addTearDown(tester.view.reset);
-      await tester.pumpWidget(MaterialApp(theme: ThemeData.dark(), home: Scaffold(body: child)));
+      await tester.pumpWidget(scoped(_graph, MaterialApp(theme: ThemeData.dark(), home: Scaffold(body: child))));
       await tester.pumpAndSettle();
       expect(tester.takeException(), isNull);
     }

apps/desktop/test/queue_panel_test.dart

@@ -6,12 +6,17 @@ import 'package:starsync/src/session/session_coordinator.dart';
 import 'package:starsync/src/shell/library_link.dart' show LinkPreview;
 import 'package:starsync/src/widgets/text_focus.dart';
 
+import 'test_graph.dart';
+
+/// This file's composition root (see test_graph.dart).
+final _graph = testGraph();
+
 void main() {
   testWidgets('Up next popover: holds the keys, Ctrl+V adds with a preview row, + Add link opens a field',
       (tester) async {
     final coord = SessionCoordinator();
     var clip = (files: const <String>[], text: 'look https://example.com/v' as String?);
-    await tester.pumpWidget(MaterialApp(
+    await tester.pumpWidget(scoped(_graph, MaterialApp(
       theme: ThemeData.dark(),
       home: Scaffold(
         body: Center(
@@ -23,7 +28,7 @@ void main() {
           ),
         ),
       ),
-    ));
+    )));
     await tester.pump();
     expect(textInputFocused(), isTrue, reason: 'the player keys rest while it is open');
     expect(find.byKey(const ValueKey('queue-add-field')), findsNothing);

apps/desktop/test/schedule_page_test.dart

@@ -1,5 +1,3 @@
-// restructure: rewrite in step 3 (Your server): "solo: the button says
-// Play"; the rest stays.
 import 'dart:convert';
 import 'dart:io';
 
@@ -16,6 +14,11 @@ import 'package:starsync/src/screens/home/picked_media.dart';
 
 import 'schedule_fake_server.dart';
 
+import 'test_graph.dart';
+
+/// This file's composition root (see test_graph.dart).
+final _graph = testGraph();
+
 /// Serves [snap] without any network; [animeFlow] is a real client (over
 /// the fake server) for the page's actions.
 class FakeRepo extends ScheduleRepository {
@@ -234,7 +237,7 @@ void main() {
     WidgetTester tester, {
     Size size = const Size(2560, 1080),
     ScheduleSnapshot Function()? snap,
-    bool solo = false,
+    bool alone = false,
     JellyfinAccounts? accounts,
   }) async {
     toasts.clear();
@@ -243,12 +246,12 @@ void main() {
     tester.view.devicePixelRatio = 1;
     addTearDown(tester.view.reset);
     final repo = FakeRepo(snap ?? snapshot, animeFlow: flow);
-    await tester.pumpWidget(
+    await tester.pumpWidget(scoped(_graph, 
       MaterialApp(
         theme: ThemeData.dark(),
         home: Scaffold(
           body: SchedulePage(
-            solo: solo,
+            alone: alone,
             repository: repo,
             accounts: accounts,
             onToast: toasts.add,
@@ -258,8 +261,7 @@ void main() {
             },
           ),
         ),
-      ),
-    );
+      )));
     await tester.pump();
     await tester.pump();
     await io(tester, rounds: 4);
@@ -269,7 +271,7 @@ void main() {
   /// Unmounts the page and lets the HttpClient's idle keep-alive timers
   /// (made in the fake clock) run out.
   Future<void> done(WidgetTester tester) async {
-    await tester.pumpWidget(const SizedBox());
+    await tester.pumpWidget(scoped(_graph, const SizedBox()));
     await tester.pump(const Duration(seconds: 20));
   }
 
@@ -482,8 +484,8 @@ void main() {
     await done(tester);
   });
 
-  testWidgets('solo: the button says Play and works', (tester) async {
-    await pumpPage(tester, solo: true);
+  testWidgets('nobody else in the server (D9): the button says Play and works', (tester) async {
+    await pumpPage(tester, alone: true);
     expect(find.text('Put it up'), findsNothing);
     final b = widgetOf<ButtonStyleButton>(tester, action(111, 3));
     expect(b.onPressed, isNotNull);

apps/desktop/test/server_isolate_test.dart

@@ -1,5 +1,5 @@
-// restructure: rewrite in step 3 (Your server): one hub with listeners
-// attached, nothing restarts, no solo mode.
+// Your server: one hub for the app's life, a network listener attached
+// by Invite and detached by Stop sharing, nothing restarts.
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
@@ -9,11 +9,15 @@ import 'package:flutter_test/flutter_test.dart';
 import 'package:hive_ce/hive.dart';
 import 'package:media_kit/media_kit.dart';
 import 'package:sync_relay_core/core.dart';
-import 'package:starsync/src/jellyfin/accounts.dart';
 import 'package:starsync/src/screens/home/picked_media.dart';
 import 'package:starsync/src/session/session_coordinator.dart';
 import 'package:starsync/src/state/server_isolate.dart';
-import 'package:starsync/src/state/session_state.dart';
+import 'package:sync_relay_server/server.dart' show SyncServer;
+
+import 'package:starsync/src/session/navigation.dart' show Place;
+
+import 'test_graph.dart';
+
 
 Future<void> _poll(
   FutureOr<bool> Function() cond,
@@ -33,11 +37,14 @@ class _Raw {
   final WebSocket ws;
   final msgs = <Map<String, Object?>>[];
   _Raw(this.ws) {
-    ws.listen((m) => msgs.add(Map<String, Object?>.from(jsonDecode('$m') as Map)));
+    ws.listen((m) => msgs.add(Map<String, Object?>.from(jsonDecode('$m') as Map)),
+        onDone: () => done.complete(ws.closeCode), onError: (_) {});
   }
 
-  static Future<_Raw> join(int port, String name, {String secret = ''}) async {
-    final r = _Raw(await WebSocket.connect('ws://127.0.0.1:$port/sync'));
+  final done = Completer<int?>();
+
+  static Future<_Raw> join(int port, String name, {String secret = '', String host = '127.0.0.1'}) async {
+    final r = _Raw(await WebSocket.connect('ws://$host:$port/sync'));
     r.ws.add(jsonEncode(HelloMessage(secret: secret, user: HelloUser(name: name)).toJson()));
     await r.next('welcome');
     return r;
@@ -66,6 +73,23 @@ Future<int> _freePort() async {
   return port;
 }
 
+/// This machine's first LAN address (the invite's); loopback when none.
+Future<String> _lanHost() async {
+  for (final i in await NetworkInterface.list(type: InternetAddressType.IPv4)) {
+    for (final a in i.addresses) {
+      if (!a.isLoopback) return a.address;
+    }
+  }
+  return '127.0.0.1';
+}
+
+List<Map> _members(Map<String, Object?> state) => (state['members'] as List).cast<Map>();
+
+void _hive(String name) {
+  MediaKit.ensureInitialized();
+  Hive.init('${Platform.environment['WT_TEST_TMP'] ?? Directory.systemTemp.path}/$name');
+}
+
 void main() {
   test('server isolate: logs, raw join, crash reported, stop frees port',
       timeout: const Timeout(Duration(minutes: 1)), () async {
@@ -108,153 +132,158 @@ void main() {
     }
   });
 
-  test('host path: isolate server, host sat out and nudging, crash leaves the session',
+  test('your server: Invite attaches the network listener and Stop sharing detaches it; '
+      'members and Up next never reset; a crash brings a new one home',
       timeout: const Timeout(Duration(minutes: 2)), () async {
-    MediaKit.ensureInitialized();
-    Hive.init(
-        '${Platform.environment['WT_TEST_TMP'] ?? Directory.systemTemp.path}/hive_isolate_test');
-    final session = SessionState.instance;
-    final port = await _freePort();
-    _Raw? friend;
-    try {
-      await session.host(
-          ConnectParams(host: '', port: port, secret: 'pw', name: 'host'),
-          ConnectForm());
-      expect(session.route.peek(), AppRoute.session);
-      await session.coordinator.playback.player.setVolume(0);
-
-      friend = await _Raw.join(port, 'friend', secret: 'pw');
-      final state = await friend.next('state',
-          where: (m) => (m['members'] as List).any((x) => (x as Map)['name'] == 'host'));
-      final hostId = ((state['members'] as List)
-          .cast<Map>()
-          .firstWhere((m) => m['name'] == 'host'))['id'];
-      // Anyone may sit the host out; its player unloads, the server serves on.
-      friend.ws.add(jsonEncode(PresenceIntent(target: '$hostId', state: Presence.away).toJson()));
-      await _poll(() => session.coordinator.selfAway.peek(), 'host sat out');
-
-      // The host nudges the friend: only the friend hears it.
-      final friendId = ((state['members'] as List)
-          .cast<Map>()
-          .firstWhere((m) => m['name'] == 'friend'))['id'];
-      session.coordinator.nudgeMember('$friendId');
-      expect((await friend.next('nudge'))['name'], 'host');
-
-      session.hostedServer!.isolate.kill(priority: Isolate.immediate);
-      await _poll(() => session.route.peek() == AppRoute.home, 'leave after crash');
-      expect(session.serverCrash.peek(), startsWith('server crashed'));
-      expect(session.hostedServer, isNull);
-      // The killed isolate's socket stays bound in-process; hosting again on
-      // the same port must still work.
-      session.serverCrash.value = null;
-      await session.host(
-          ConnectParams(host: '', port: port, secret: 'pw', name: 'host'),
-          ConnectForm());
-      expect(session.route.peek(), AppRoute.session);
-      final again = await _Raw.join(port, 'again', secret: 'pw');
-      await again.ws.close();
-      await session.leave();
-      expect(session.hostedServer, isNull);
-    } finally {
-      await friend?.ws.close();
-      await session.coordinator.leave(silent: true);
-      await session.stopServer();
-    }
-  });
-
-  test('host path: a Jellyfin pick goes up as a ref with the host relay; File swap',
-      timeout: const Timeout(Duration(minutes: 2)), () async {
-    MediaKit.ensureInitialized();
+    _hive('hive_your_server_test');
+    final graph = testGraph();
+    final coord = graph.coordinator;
+    final yours = graph.yourServer;
     final tmp = Platform.environment['WT_TEST_TMP'] ?? Directory.systemTemp.path;
-    Hive.init('$tmp/hive_isolate_jf_test');
-    const sid = 'abcdefabcdefabcdefabcdefabcdef12';
-    final accounts = JellyfinAccounts.instance;
-    await accounts.ensureLoaded(validate: false);
-    // An unreachable Jellyfin: only the wire and the relay flag matter here.
-    await accounts.link(
-        baseUrl: 'http://127.0.0.1:9',
-        server: const JellyfinServerInfo(id: sid, name: 'J', version: '10.11.11'),
-        auth: const JellyfinAuthResult(
-            accessToken: 'HOSTTOKEN', user: JellyfinUser(id: 'u', name: 'u'), serverId: sid));
-    final session = SessionState.instance;
+    final file = File('$tmp/your server file.mkv')..writeAsBytesSync(List.filled(4096, 7));
     final port = await _freePort();
     _Raw? friend;
-    final file = File('$tmp/host file swap.mkv')..writeAsBytesSync(List.filled(4096, 7));
     try {
-      await session.host(
-          ConnectParams(
-              host: '',
-              port: port,
-              secret: '',
-              name: 'host',
-              media: const HelloMedia(
-                  name: 'Pilot',
-                  size: 0,
-                  duration: 0,
-                  jellyfin: JellyfinRef(serverId: sid, itemId: 'e1e1e1e1e1e1e1e1e1e1e1e1e1e1e1e1', title: 'Pilot'))),
-          ConnectForm());
-      await session.coordinator.playback.player.setVolume(0);
-      friend = await _Raw.join(port, 'friend');
-      final state = await friend.next('state', where: (m) => m['media'] != null);
-      final media = state['media'] as Map;
-      expect(media['jellyfin'], isA<Map>());
-      expect(media.containsKey('url'), isFalse);
-      expect(state['relay'], isTrue, reason: "the host's own sign-in relays for guests");
-      expect(jsonEncode(state), isNot(contains('HOSTTOKEN')));
-
-      expect(await session.coordinator.swapFile(file.path), isNull);
-      final swapped = await friend.next('state',
-          where: (m) => (m['media'] as Map?)?['name'] == 'host file swap.mkv');
-      expect((swapped['media'] as Map)['jellyfin'], isNull);
-      expect(swapped['relay'], isNull);
-      expect(await session.coordinator.swapFile('$tmp/missing.mkv'), contains('not found'));
-    } finally {
-      await friend?.ws.close();
-      await session.coordinator.leave(silent: true);
-      await session.stopServer();
-      await accounts.signOut(sid);
-      if (file.existsSync()) file.deleteSync();
-    }
-  });
-
-  test('solo: loopback-only server; inviting friends hosts the same media',
-      timeout: const Timeout(Duration(minutes: 2)), () async {
-    MediaKit.ensureInitialized();
-    final tmp = Platform.environment['WT_TEST_TMP'] ?? Directory.systemTemp.path;
-    Hive.init('$tmp/hive_isolate_solo_test');
-    final session = SessionState.instance;
-    final port = await _freePort();
-    _Raw? friend;
-    final file = File('$tmp/solo carry.mkv')..writeAsBytesSync(List.filled(4096, 7));
-    session.route.value = AppRoute.home; // the tests above leave it set
-    try {
-      await session.startSolo(const ConnectParams(host: '127.0.0.1', port: 0, secret: '', name: 'me'));
-      expect(session.route.peek(), AppRoute.session);
-      expect(session.solo.peek(), isTrue);
-      await session.coordinator.playback.player.setVolume(0);
-      final soloPort = session.hostedServer!.port;
-      // Reachable on loopback only: a LAN address of this machine is refused.
-      final lan = [
-        for (final i in await NetworkInterface.list(type: InternetAddressType.IPv4))
-          for (final a in i.addresses)
-            if (!a.isLoopback) a,
-      ];
-      if (lan.isNotEmpty) {
-        await expectLater(Socket.connect(lan.first, soloPort, timeout: const Duration(seconds: 3)),
+      expect(await graph.navigation.goHome(), isTrue);
+      expect(graph.navigation.place.peek(), Place.yours);
+      await coord.playback.player.setVolume(0);
+      final ownPort = yours.port.peek()!;
+      final me = coord.connection.memberId;
+      expect(me, isNotEmpty);
+      // Only this app can reach it: a LAN address of this machine is refused.
+      final lan = await _lanHost();
+      if (lan != '127.0.0.1') {
+        await expectLater(Socket.connect(lan, ownPort, timeout: const Duration(seconds: 3)),
             throwsA(isA<SocketException>()));
       }
-      expect(await session.coordinator.swapPicked(FileMedia(file.path)), isNull);
-      await _poll(() => session.coordinator.serverState.peek()?.media?['name'] == 'solo carry.mkv', 'solo media');
+      expect(coord.alone.peek(), isTrue);
+      expect(await coord.swapPicked(FileMedia(file.path)), isNull);
+      await _poll(() => coord.serverState.peek()?.media?['name'] == 'your server file.mkv', 'media up');
 
-      await session.host(ConnectParams(host: '', port: port, secret: 'pw', name: 'me'), ConnectForm());
-      expect(session.solo.peek(), isFalse);
-      expect(session.route.peek(), AppRoute.session);
-      friend = await _Raw.join(port, 'friend', secret: 'pw');
-      await friend.next('state', where: (m) => (m['media'] as Map?)?['name'] == 'solo carry.mkv');
+      graph.forms.form
+        ..hostPort = '$port'
+        ..hostSecret = 'pw';
+      final invite = await yours.invite();
+      expect(invite.port, port);
+      expect(invite.password, isTrue);
+      expect(yours.shared.peek(), invite);
+      expect(identical(await yours.invite(), invite), isTrue, reason: 'already shared: the same invite');
+
+      friend = await _Raw.join(port, 'friend', secret: 'pw', host: lan);
+      final state = await friend.next('state', where: (m) => _members(m).length == 2 && m['media'] != null);
+      expect(_members(state).firstWhere((m) => m['id'] == me)['host'], isTrue);
+      friend.ws.add(jsonEncode({
+        't': 'queue',
+        'op': 'add',
+        'item': {
+          'media': {'name': 'b', 'size': 0, 'duration': 0, 'url': 'http://example.com/b.mp4'},
+          'how': 'direct',
+          'title': 'B',
+        },
+      }));
+      await _poll(() => coord.queue.items.peek().length == 1, 'queued by the friend');
+      expect(coord.alone.peek(), isFalse);
+      // Anyone may sit the host out; its player unloads, the server serves on.
+      friend.ws.add(jsonEncode(PresenceIntent(target: me, state: Presence.away).toJson()));
+      await _poll(() => coord.selfAway.peek(), 'host sat out');
+      final friendId = _members(state).firstWhere((m) => m['name'] == 'friend')['id'];
+      coord.nudgeMember('$friendId');
+      expect((await friend.next('nudge'))['name'], isNotEmpty);
+      coord.joinBack();
+
+      await yours.stopSharing();
+      expect(await friend.done.future.timeout(const Duration(seconds: 5)), CloseCodes.closed,
+          reason: 'told: their app does not retry');
+      await _poll(() => coord.alone.peek(), 'alone again');
+      expect(coord.connection.memberId, me, reason: 'the same member, never reconnected');
+      expect(coord.restarts.peek(), 0);
+      expect(coord.queue.items.peek(), hasLength(1), reason: 'Up next stays');
+      expect(coord.serverState.peek()?.media?['name'], 'your server file.mkv');
+      expect(yours.port.peek(), ownPort, reason: 'nothing restarted');
+      final freed = await ServerSocket.bind(InternetAddress.anyIPv4, port);
+      await freed.close();
+
+      // A crash: said, and home again on a new server.
+      yours.server!.isolate.kill(priority: Isolate.immediate);
+      await _poll(() => yours.crash.peek() != null, 'crash reported');
+      await _poll(() => graph.navigation.place.peek() == Place.yours && yours.port.peek() != null, 'home again');
+      expect(yours.crash.peek(), startsWith('server crashed'));
     } finally {
       await friend?.ws.close();
-      await session.leave();
+      await graph.navigation.leave();
+      await yours.stop();
       if (file.existsSync()) file.deleteSync();
     }
   });
+
+  test('a friend\'s server and back: yours keeps what plays and Up next', timeout: const Timeout(Duration(minutes: 2)),
+      () async {
+    _hive('hive_your_server_switch_test');
+    final graph = testGraph();
+    final coord = graph.coordinator;
+    final yours = graph.yourServer;
+    final theirs = SyncServer(const AppConfig(port: 0, secret: '', name: "Bob's server"));
+    await theirs.start();
+    try {
+      expect(await graph.navigation.goHome(), isTrue);
+      await coord.playback.player.setVolume(0);
+      final ownPort = yours.port.peek();
+      coord.connection.sendSwap(const HelloMedia(name: 'mine', size: 0, duration: 0, url: 'http://127.0.0.1:9/mine.mp4'));
+      expect(await coord.queue.add(const LinkMedia('http://127.0.0.1:9/next.mp4', relay: LinkRelay.direct, anyway: true)), isNull);
+      await _poll(() => coord.serverState.peek()?.media?['name'] == 'mine' && coord.queue.items.peek().length == 1,
+          'media and Up next on your server');
+
+      await graph.navigation.join(ConnectParams(host: '127.0.0.1', port: theirs.boundPort, secret: '', name: 'me'));
+      expect(graph.navigation.place.peek(), Place.friend);
+      expect(graph.navigation.serverLabel.peek(), "Bob's server");
+      expect(coord.hostFile, isNull, reason: 'not your server');
+      await _poll(() => theirs.hub.engine.members.length == 1, 'in their server');
+      expect(yours.port.peek(), ownPort, reason: 'yours stays up, quiet');
+      expect(graph.forms.recents.peek().first.port, '${theirs.boundPort}');
+
+      expect(await graph.navigation.leaveFriend(), isTrue);
+      expect(graph.navigation.place.peek(), Place.yours);
+      await _poll(() => coord.serverState.peek()?.media?['name'] == 'mine', 'your media again');
+      expect(coord.queue.items.peek(), hasLength(1));
+      expect(yours.port.peek(), ownPort);
+      await _poll(() => theirs.hub.engine.members.isEmpty, 'left theirs with bye');
+    } finally {
+      await graph.navigation.leave();
+      await yours.stop();
+      await theirs.stop();
+    }
+  });
+
+  test('a friend stops sharing: told, and you are back home on yours', timeout: const Timeout(Duration(minutes: 2)),
+      () async {
+    _hive('hive_your_server_closed_test');
+    final me = testGraph();
+    final bob = testGraph();
+    final port = await _freePort();
+    try {
+      expect(await bob.navigation.goHome(), isTrue);
+      await bob.coordinator.playback.player.setVolume(0);
+      bob.forms.form
+        ..hostPort = '$port'
+        ..hostSecret = '';
+      final invite = await bob.yourServer.invite();
+      expect(await me.navigation.goHome(), isTrue);
+      await me.coordinator.playback.player.setVolume(0);
+      final mine = me.yourServer.port.peek();
+      await me.navigation.join(ConnectParams(host: '127.0.0.1', port: invite.port, secret: '', name: 'me'));
+      expect(me.navigation.place.peek(), Place.friend);
+      await _poll(() => !bob.coordinator.alone.peek(), 'bob sees me');
+
+      await bob.yourServer.stopSharing();
+      await _poll(() => me.navigation.place.peek() == Place.yours, 'back home');
+      expect(me.yourServer.port.peek(), mine, reason: 'the same server as before');
+      await _poll(() => me.notifier.toasts.peek().any((t) => t.text.contains('stopped sharing')), 'told why');
+      await _poll(() => bob.coordinator.alone.peek(), 'bob alone again');
+    } finally {
+      await me.navigation.leave();
+      await bob.navigation.leave();
+      await me.yourServer.stop();
+      await bob.yourServer.stop();
+    }
+  });
 }

apps/desktop/test/shell_test.dart

@@ -1,5 +1,3 @@
-// restructure: rewrite in step 3 (Your server): the solo strip and Invite
-// friends.
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
@@ -19,10 +17,17 @@ import 'package:starsync/src/shell/session_player.dart';
 import 'package:starsync/src/shell/settings_tab.dart' show SettingsTab;
 import 'package:starsync/src/shell/toasts.dart';
 import 'package:starsync/src/session/session_coordinator.dart' show ToastItem;
-import 'package:starsync/src/state/session_state.dart';
 import 'package:starsync/src/state/settings.dart';
 import 'package:starsync/src/update/update_controller.dart';
 
+import 'package:starsync/src/session/invite.dart' show Invite;
+import 'package:starsync/src/session/navigation.dart' show Place;
+
+import 'test_graph.dart';
+
+/// This file's composition root (see test_graph.dart).
+final _graph = testGraph();
+
 /// Stands in for media_kit's `Video` (which hangs flutter_test) and
 /// counts how often one is created.
 class FakeVideo extends StatefulWidget {
@@ -55,7 +60,7 @@ MemberView member(String id, String name, {bool ready = false, bool gone = false
         presence: gone ? Presence.gone : Presence.watching);
 
 void main() {
-  final session = SessionState.instance;
+  final session = _graph;
   final coord = session.coordinator;
 
   void online(List<MemberView> members, {bool media = true}) {
@@ -68,16 +73,16 @@ void main() {
       media: media ? {'name': 'Movie.mkv', 'size': 1, 'duration': 0} : null,
       members: members,
     );
-    session.route.value = AppRoute.session;
+    session.navigation.place.value = Place.friend;
   }
 
   setUp(() {
     FakeVideo.created = 0;
-    session.recents.value = const [];
+    session.forms.recents.value = const [];
   });
 
   tearDown(() {
-    session.route.value = AppRoute.home;
+    session.navigation.place.value = Place.none;
     coord.serverState.value = null;
     coord.playback.alive.value = false;
     session.notifier.clear();
@@ -87,7 +92,7 @@ void main() {
     tester.view.physicalSize = size;
     tester.view.devicePixelRatio = 1;
     addTearDown(tester.view.reset);
-    await tester.pumpWidget(MaterialApp(
+    await tester.pumpWidget(scoped(_graph, MaterialApp(
       theme: ThemeData.dark(),
       home: AppShell(
         updates: updates ?? UpdateController(currentVersion: '0.0.0-dev'),
@@ -97,7 +102,7 @@ void main() {
         // A real probe (network, yt-dlp) never answers on the test clock.
         linkProbe: (url) async => LinkProbe.file(Uri.parse(url), 1000),
       ),
-    ));
+    )));
     await tester.pumpAndSettle();
   }
 
@@ -148,14 +153,53 @@ void main() {
   });
 
   group('party strip', () {
-    testWidgets('offline: Join and Host, no party', (tester) async {
+    testWidgets('home, alone: a plain player\'s strip, Join a friend and Invite (once your server runs)',
+        (tester) async {
       await pumpShell(tester, const Size(1280, 800));
       expect(find.byKey(const ValueKey('strip-join')), findsOneWidget);
-      expect(find.byKey(const ValueKey('strip-host')), findsOneWidget);
-      expect(find.text('Offline'), findsOneWidget);
+      expect(find.byKey(const ValueKey('strip-host')), findsNothing, reason: 'no Host: your server is always there');
       expect(find.byKey(const ValueKey('party-avatars')), findsNothing);
       expect(find.byKey(const ValueKey('strip-leave')), findsNothing);
+      expect(find.byKey(const ValueKey('strip-chat')), findsNothing);
       expect(tester.getSize(find.byType(PartyStrip)).height, partyStripHeight);
+      ButtonStyleButton invite() => tester.widget<ButtonStyleButton>(find.byKey(const ValueKey('strip-invite')));
+      expect(invite().onPressed, isNull, reason: 'your server is not up yet');
+      final yours = session.yourServer;
+      yours.port.value = 40000;
+      addTearDown(() {
+        yours.port.value = null;
+        yours.shared.value = null;
+      });
+      // On your own server with only you in it: still the plain strip.
+      session.navigation.place.value = Place.yours;
+      coord.serverState.value = StateBroadcast(
+          eventId: 1, transport: 'held', position: 0, serverTime: DateTime.now().toUtc(), mediaId: 0,
+          members: [member('', 'Me')]);
+      await tester.pumpAndSettle();
+      expect(invite().onPressed, isNotNull);
+      expect(find.byKey(const ValueKey('party-avatars')), findsNothing);
+      expect(find.byKey(const ValueKey('strip-chat')), findsNothing);
+      expect(find.byKey(const ValueKey('sharing-chip')), findsNothing);
+      // Shared, nobody came yet: the chip says so (and opens the invite).
+      yours.shared.value = const Invite(host: '192.168.1.20', port: 8080);
+      await tester.pumpAndSettle();
+      expect(find.byKey(const ValueKey('sharing-chip')), findsOneWidget);
+      expect(find.text('port 8080'), findsOneWidget);
+      await tester.tap(find.byKey(const ValueKey('sharing-chip')));
+      await tester.pumpAndSettle();
+      expect(find.byKey(const ValueKey('stop-sharing')), findsOneWidget);
+      await tester.tapAt(const Offset(40, 700));
+      await tester.pumpAndSettle();
+      // A friend came: the party, with Invite and no Leave (it is yours).
+      coord.serverState.value = StateBroadcast(
+          eventId: 2, transport: 'held', position: 0, serverTime: DateTime.now().toUtc(), mediaId: 0,
+          members: [member('', 'Me'), member('b', 'Bob')]);
+      await tester.pumpAndSettle();
+      expect(find.byKey(const ValueKey('party-avatars')), findsOneWidget);
+      expect(find.byKey(const ValueKey('strip-chat')), findsOneWidget);
+      expect(find.byKey(const ValueKey('strip-invite')), findsOneWidget);
+      expect(find.byKey(const ValueKey('strip-leave')), findsNothing);
+      expect(find.text('Your server'), findsOneWidget);
     });
 
     testWidgets('online: avatars, server and readiness, chat, Leave', (tester) async {
@@ -179,30 +223,7 @@ void main() {
       expect(find.text('Leave server?'), findsOneWidget);
       await tester.tap(find.text('Cancel'));
       await tester.pumpAndSettle();
-      expect(session.route.value, AppRoute.session);
-    });
-
-    testWidgets('solo: just you, Invite friends opens the host card, Stop asks nothing', (tester) async {
-      await pumpShell(tester, const Size(1280, 800));
-      session.solo.value = true;
-      addTearDown(() => session.solo.value = false);
-      online([member('me', 'Me')], media: false);
-      await tester.pumpAndSettle();
-      expect(find.byKey(const ValueKey('solo-chip')), findsOneWidget);
-      expect(find.byKey(const ValueKey('party-avatars')), findsNothing);
-      expect(find.byKey(const ValueKey('strip-chat')), findsNothing);
-      expect(find.byKey(const ValueKey('welcome-band')), findsNothing);
-      await tester.tap(find.byKey(const ValueKey('strip-invite')));
-      await tester.pumpAndSettle();
-      expect(find.text('Invite friends'), findsWidgets);
-      expect(find.text('Start hosting'), findsOneWidget);
-      await tester.tapAt(const Offset(5, 790));
-      await tester.pumpAndSettle();
-      await tester.tap(find.byKey(const ValueKey('strip-leave')));
-      await tester.pumpAndSettle();
-      expect(find.text('Leave server?'), findsNothing);
-      expect(session.route.value, AppRoute.home);
-      expect(session.solo.value, isFalse);
+      expect(session.navigation.place.value, Place.friend);
     });
 
     testWidgets('compact below 1100 px: 3 avatars, no server text', (tester) async {
@@ -221,8 +242,8 @@ void main() {
   group('popovers', () {
     testWidgets('members card opens from the avatars and closes outside', (tester) async {
       await pumpShell(tester, const Size(1280, 800));
-      session.serverVersion.value = '1.3.0-dev.1';
-      addTearDown(() => session.serverVersion.value = '');
+      session.navigation.serverVersion.value = '1.3.0-dev.1';
+      addTearDown(() => session.navigation.serverVersion.value = '');
       online([member('a', 'Alex', ready: true, app: '1.3.0-dev.1'), ...party.skip(1)], media: false);
       await tester.pumpAndSettle();
       await tester.tap(find.byKey(const ValueKey('avatar-stack')));
@@ -255,7 +276,7 @@ void main() {
       await tester.tap(find.byKey(const ValueKey('strip-profile')));
       await tester.pumpAndSettle();
       expect(find.byType(ProfileCard), findsOneWidget);
-      expect(find.text('offline'), findsOneWidget);
+      expect(find.text('just you'), findsOneWidget);
       await tester.tap(find.text('About'));
       await tester.pumpAndSettle();
       expect(find.byType(ProfileCard), findsNothing);
@@ -263,7 +284,7 @@ void main() {
     });
 
     testWidgets('showPopover fades and scales in, Esc closes it', (tester) async {
-      await tester.pumpWidget(MaterialApp(
+      await tester.pumpWidget(scoped(_graph, MaterialApp(
         home: Builder(
           builder: (context) => Center(
             child: TextButton(
@@ -272,7 +293,7 @@ void main() {
             ),
           ),
         ),
-      ));
+      )));
       await tester.tap(find.text('open'));
       await tester.pump();
       await tester.pump(easeTime ~/ 2);
@@ -303,7 +324,7 @@ void main() {
     await tester.sendKeyUpEvent(LogicalKeyboardKey.controlLeft);
     await tester.pumpAndSettle();
     expect(find.byKey(const ValueKey('handoff-card')), findsOneWidget);
-    expect(find.text('Open in Link'), findsOneWidget); // offline
+    expect(find.text('Open in Link'), findsOneWidget); // alone
     await tester.tap(find.byKey(const ValueKey('handoff-openLink')));
     await tester.pumpAndSettle();
     expect(find.byKey(const ValueKey('handoff-card')), findsNothing);
@@ -318,15 +339,15 @@ void main() {
     final before = p.push;
     p.push = ({String? name, String? avatar}) => pushed.add(name);
     addTearDown(() => p.push = before);
-    session.lastForm.name = 'Old';
+    session.forms.form.name = 'Old';
     p.name.value = 'Old';
-    await tester.pumpWidget(MaterialApp(
+    await tester.pumpWidget(scoped(_graph, MaterialApp(
       home: Scaffold(body: Center(child: ProfileCard(onOpenSettings: (_) {}))),
-    ));
+    )));
     await tester.enterText(find.byKey(const ValueKey('profile-name')), 'Neo');
     await tester.pump();
     expect(p.name.value, 'Neo');
-    expect(session.lastForm.name, 'Neo');
+    expect(session.forms.form.name, 'Neo');
     // Typing settles before it is sent, once.
     expect(pushed, isEmpty);
     await tester.pump(const Duration(milliseconds: 700));
@@ -391,7 +412,7 @@ void main() {
     // Never rebuilt from scratch on the way.
     expect(FakeVideo.created, 1);
     // Offline: no player at all.
-    session.route.value = AppRoute.home;
+    session.navigation.place.value = Place.none;
     await tester.pumpAndSettle();
     expect(videos, findsNothing);
     expect(tester.takeException(), isNull);
@@ -439,7 +460,7 @@ void main() {
   });
 
   testWidgets("toasts slide in and leave when the Notifier's time is up", (tester) async {
-    await tester.pumpWidget(const MaterialApp(home: Scaffold(body: PartyToasts())));
+    await tester.pumpWidget(scoped(_graph, const MaterialApp(home: Scaffold(body: PartyToasts()))));
     session.notifier.notify(const Copied('Shaders off'));
     await tester.pump();
     await tester.pump();
@@ -484,7 +505,7 @@ void main() {
       final down = tester.getRect(find.byType(ToastCard));
       expect(down.bottom, closeTo(body.bottom - AppShellState.toastInset, 1));
       expect(down.bottom, greaterThan(up.bottom));
-      session.route.value = AppRoute.home;
+      session.navigation.place.value = Place.none;
       await tester.pump(const Duration(seconds: 6));
       await tester.pumpAndSettle();
     });

apps/desktop/test/singletons_test.dart

@@ -0,0 +1,47 @@
+import 'dart:io';
+
+import 'package:flutter_test/flutter_test.dart';
+
+/// The app's own `.instance` singletons and how often `lib` reaches for
+/// each. Systems get their dependencies through the composition root
+/// (`AppGraph`, widgets through `AppScope`); this list may only shrink.
+/// Lower a number when a use goes; never raise one or add a class.
+const baseline = {
+  'AppSettings': 55,
+  'JellyfinAccounts': 10,
+  'UpdateController': 8,
+  'Profile': 8,
+  'FolderStore': 6,
+  'AppYtDlp': 4,
+  'RecentLinks': 3,
+};
+
+void main() {
+  test('no new .instance singletons, and no more uses of the old ones', () {
+    final files = Directory('lib')
+        .listSync(recursive: true)
+        .whereType<File>()
+        .where((f) => f.path.endsWith('.dart'))
+        .toList();
+    final sources = [for (final f in files) f.readAsStringSync()];
+    // The app's own classes (framework singletons like
+    // `WidgetsBinding.instance` are not counted).
+    final classes = {
+      for (final s in sources)
+        for (final m in RegExp(r'^(?:abstract |final |base )*class (\w+)', multiLine: true).allMatches(s)) m.group(1)!,
+    };
+    final counts = <String, int>{};
+    for (final s in sources) {
+      for (final m in RegExp(r'\b([A-Z]\w*)\.instance\b').allMatches(s)) {
+        final name = m.group(1)!;
+        if (classes.contains(name)) counts[name] = (counts[name] ?? 0) + 1;
+      }
+    }
+    final grown = {
+      for (final e in counts.entries)
+        if (e.value > (baseline[e.key] ?? 0)) e.key: '${e.value} (baseline ${baseline[e.key] ?? 'none'})',
+    };
+    expect(grown, isEmpty,
+        reason: 'pass the system in through AppGraph / AppScope instead of a new `.instance` use or singleton');
+  });
+}

apps/desktop/test/test_graph.dart

@@ -0,0 +1,14 @@
+// Test support (not a test): the app's composition root for tests.
+import 'package:flutter/widgets.dart';
+import 'package:starsync/src/app/app_graph.dart';
+import 'package:starsync/src/screens/home/health_probe.dart';
+import 'package:starsync/src/session/identity.dart' show ClientIdentity;
+
+/// One graph per test file, like the app's one per run: nothing starts
+/// until a test calls `navigation.start()` (or `goHome`), so widget tests
+/// see the app before your server is up.
+AppGraph testGraph({HealthGetter healthGet = defaultHealthGet}) =>
+    AppGraph.build(identity: ClientIdentity.ephemeral(), healthGet: healthGet);
+
+/// [child] under [graph]'s [AppScope].
+Widget scoped(AppGraph graph, Widget child) => AppScope(graph: graph, child: child);

apps/desktop/test/text_focus_test.dart

@@ -2,20 +2,25 @@ import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:starsync/src/widgets/text_focus.dart';
 
+import 'test_graph.dart';
+
+/// This file's composition root (see test_graph.dart).
+final _graph = testGraph();
+
 void main() {
   // Regression: the old FocusNode-parent walk never met EditableText, so
   // session shortcuts (Space, arrows, F) fired while typing in chat.
   testWidgets('text field focus is detected, buttons are not', (tester) async {
     final field = FocusNode();
     final button = FocusNode();
-    await tester.pumpWidget(MaterialApp(
+    await tester.pumpWidget(scoped(_graph, MaterialApp(
       home: Scaffold(
         body: Column(children: [
           TextField(focusNode: field),
           TextButton(focusNode: button, onPressed: () {}, child: const Text('b')),
         ]),
       ),
-    ));
+    )));
     expect(textInputFocused(), isFalse);
 
     field.requestFocus();
@@ -33,9 +38,9 @@ void main() {
 
   testWidgets('focus under a KeyboardClaim counts as typing', (tester) async {
     final claimed = FocusNode();
-    await tester.pumpWidget(MaterialApp(
+    await tester.pumpWidget(scoped(_graph, MaterialApp(
       home: KeyboardClaim(child: Focus(focusNode: claimed, child: const SizedBox())),
-    ));
+    )));
     expect(textInputFocused(), isFalse);
     claimed.requestFocus();
     await tester.pump();

apps/desktop/test/volume_readout_test.dart

@@ -6,16 +6,20 @@ import 'package:media_kit_video/media_kit_video.dart' show VideoState;
 import 'package:starsync/src/controls/model/controls_prefs.dart';
 import 'package:starsync/src/controls/frame.dart';
 import 'package:starsync/src/shell/session_player.dart';
-import 'package:starsync/src/state/session_state.dart';
 import 'package:starsync/src/state/settings.dart';
 
+import 'test_graph.dart';
+
+/// This file's composition root (see test_graph.dart).
+final _graph = testGraph();
+
 // The wheel anywhere on the full player flashes the volume readout, in
 // both skins, windowed and fullscreen, with the controls up or hidden.
 // The picture is a black box with the session's controls on it (never a
 // media_kit `Video`).
 
 void main() {
-  final coord = SessionState.instance.coordinator;
+  final coord = _graph.coordinator;
   final s = AppSettings.instance;
 
   // A real player for the volume steps to go to. Never disposed: the
@@ -46,7 +50,7 @@ void main() {
       for (final fullscreen in [false, true]) {
         final what = '${skin.name}, ${fullscreen ? 'fullscreen' : 'windowed'}';
         s.controlsSkin.value = skin;
-        await tester.pumpWidget(MaterialApp(
+        await tester.pumpWidget(scoped(_graph, MaterialApp(
           theme: ThemeData.dark(),
           home: Scaffold(
             body: SessionPlayer(
@@ -68,7 +72,7 @@ void main() {
               ]),
             ),
           ),
-        ));
+        )));
         await tester.pump();
         expect(opacity(), 0, reason: '$what: nothing before a step');
 
@@ -91,7 +95,7 @@ void main() {
         expect(opacity(), 0, reason: '$what: gone after the second');
       }
     }
-    await tester.pumpWidget(const SizedBox());
+    await tester.pumpWidget(scoped(_graph, const SizedBox()));
     await tester.pump(const Duration(seconds: 5));
   });
 }