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/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);