Restructure step 2: Status as one computed level, the Notifier's real policy, system notifications

- Status: computed from connection, presence, hold, relay, player facts;
  no setters (health writes and HealthStatus gone); pill, strip and
  source line read it; transitions go to the Notifier.
- Notifier: noticeFor(event, context) with self presence, alone, window
  activity, playing and prefs; toasts for joins/leaves/returns/swaps/
  Up next adds (with picture)/problems/chat, the rest logged; while
  sitting out only chat, nudges, starting, Up next (+ joins if chosen);
  alone no social notices; replayed lines logged; owns its toast timer.
- System notifications (flutter_local_notifications: D-Bus on Linux,
  WinRT on Windows) when the window isn't focused; a click focuses it.
- Toasts sit above the control bar and move with it.
- Versions: each member's in the members card and avatar tooltip,
  the server's in the card header; the strip no longer shows it.

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

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

@@ -0,0 +1,100 @@
+import 'dart:io';
+
+import 'package:flutter/foundation.dart';
+import 'package:flutter_local_notifications/flutter_local_notifications.dart';
+
+import '../desktop_entry.dart' show appId;
+import '../ports/system_notifications.dart';
+
+/// [SystemNotifications] on the desktop, through flutter_local_notifications'
+/// platform plugins (used directly, not through its facade, so the platform
+/// is picked by the OS and not by Flutter's target platform):
+/// - Linux: `org.freedesktop.Notifications` over D-Bus (pure Dart), with the
+///   app's icon (the bundled PNG, else the launcher entry's icon by name);
+///   a click is the notification's default action.
+/// - Windows: toast notifications (WinRT), the app's name and icon, a click
+///   activates the app while it runs (an unpackaged app has no history).
+/// Silent: the app plays its own sound for the same notice. Anything that
+/// fails (no notification daemon, no session bus) is logged and dropped.
+class DesktopNotifications implements SystemNotifications {
+  DesktopNotifications({this.appName = 'Starsync'});
+
+  final String appName;
+  void Function(String payload)? _onClick;
+  Future<bool>? _ready;
+  LinuxFlutterLocalNotificationsPlugin? _linux;
+  FlutterLocalNotificationsWindows? _windows;
+  // Tag -> id, so a notification with the same tag replaces the last one.
+  final _ids = <String, int>{};
+  int _next = 1;
+
+  @override
+  set onClick(void Function(String payload)? handler) => _onClick = handler;
+
+  void _clicked(NotificationResponse r) => _onClick?.call(r.payload ?? '');
+
+  /// The bundled 256 px icon next to the executable (a release or a
+  /// `flutter run` build), else the icon the launcher entry installed.
+  static LinuxNotificationIcon _linuxIcon() {
+    final exe = File(Platform.resolvedExecutable).parent.path;
+    final png = File('$exe/data/flutter_assets/assets/icon/icon_256.png');
+    return png.existsSync() ? FilePathLinuxIcon(png.path) : ThemeLinuxIcon(appId);
+  }
+
+  Future<bool> _init() => _ready ??= () async {
+        try {
+          if (Platform.isLinux) {
+            final p = _linux = LinuxFlutterLocalNotificationsPlugin();
+            return await p.initialize(
+                  settings: LinuxInitializationSettings(defaultActionName: 'Open', defaultIcon: _linuxIcon()),
+                  onDidReceiveNotificationResponse: _clicked,
+                ) ??
+                false;
+          }
+          if (Platform.isWindows) {
+            final exe = File(Platform.resolvedExecutable).parent.path;
+            final icon = File('$exe/data/flutter_assets/assets/icon/icon_256.png');
+            final p = _windows = FlutterLocalNotificationsWindows();
+            return await p.initialize(
+              settings: WindowsInitializationSettings(
+                appName: appName,
+                appUserModelId: 'Foxyz.Starsync',
+                guid: '6c0f4b4e-3e8a-4b8e-9d0c-5a7f2b1e9c31',
+                iconPath: icon.existsSync() ? icon.path : null,
+              ),
+              onDidReceiveNotificationResponse: _clicked,
+            );
+          }
+        } catch (e) {
+          debugPrint('system notifications unavailable: $e');
+        }
+        return false;
+      }();
+
+  @override
+  Future<void> show({required String title, required String body, String tag = '', String payload = ''}) async {
+    if (!await _init()) return;
+    final id = tag.isEmpty ? _next++ : _ids[tag] ??= _next++;
+    try {
+      if (_linux case final p?) {
+        await p.show(
+          id: id,
+          title: title,
+          body: body,
+          payload: payload,
+          notificationDetails: const LinuxNotificationDetails(suppressSound: true),
+        );
+      } else if (_windows case final p?) {
+        await p.show(
+          id: id,
+          title: title,
+          body: body,
+          payload: payload,
+          notificationDetails: WindowsNotificationDetails(audio: WindowsNotificationAudio.silent()),
+        );
+      }
+    } catch (e) {
+      debugPrint('system notification failed: $e');
+    }
+  }
+}

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

@@ -1,6 +1,7 @@
 import '../../playback/yt_dlp_app.dart';
 import '../ports/ports.dart';
 import 'desktop_folders.dart';
+import 'desktop_notifications.dart';
 import 'desktop_shell.dart';
 import 'desktop_urls.dart';
 
@@ -12,6 +13,6 @@ Ports desktopPorts() {
     urls: urls,
     folders: const DesktopFolders(urls),
     links: AppYtDlp.instance,
-    notifications: const NoSystemNotifications(),
+    notifications: DesktopNotifications(),
   );
 }

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

@@ -97,6 +97,17 @@ class DesktopShell implements ShellPort {
     }
   }
 
+  @override
+  Future<void> focus() async {
+    try {
+      if (await windowManager.isMinimized()) await windowManager.restore();
+      if (!await windowManager.isVisible()) await windowManager.show();
+      await windowManager.focus();
+    } catch (e) {
+      debugPrint('window focus failed: $e');
+    }
+  }
+
   @override
   Future<void> requestAttention() => requestWindowAttention();
 

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

@@ -1,20 +1,8 @@
 import 'package:flutter/widgets.dart';
 
-/// Where the app window stands, for auto sit-out
-/// ([ShellPort.watchActivity]).
-enum WindowActivity {
-  /// The window has the keyboard focus.
-  focused,
+import 'window_activity.dart';
 
-  /// Shown, but another window has the focus.
-  unfocused,
-
-  /// Minimised to the taskbar.
-  minimised,
-
-  /// Hidden (closing, or a platform that hides instead of minimising).
-  hidden,
-}
+export 'window_activity.dart';
 
 /// What the clipboard holds for a paste: its files, else its text.
 typedef Paste = ({List<String> files, String? text});
@@ -54,6 +42,10 @@ abstract interface class ShellPort {
   Future<void> hide();
   Future<void> quit();
 
+  /// Brings the window up and gives it the focus (restored when
+  /// minimised, shown when hidden): a click on a system notification.
+  Future<void> focus();
+
   /// Points the desktop at the window when it is not focused (taskbar
   /// flash, urgency hint); nothing when it is.
   Future<void> requestAttention();

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

@@ -1,14 +1,23 @@
 /// Notifications outside the window (the desktop's notification center,
-/// Android's shade). The policy that uses them comes with the Notifier.
+/// Android's shade). The Notifier decides what goes out here (see
+/// `noticeFor`); the port only shows them and reports clicks.
 abstract interface class SystemNotifications {
-  /// Shows [title] / [body]; replaces the one with the same [tag].
-  Future<void> show({required String title, required String body, String tag = ''});
+  /// Shows [title] / [body] with the app's name and icon; one with the
+  /// same [tag] replaces it. [payload] comes back to [onClick].
+  Future<void> show({required String title, required String body, String tag = '', String payload = ''});
+
+  /// Called with a notification's payload when the user clicks it (set
+  /// once, by the Notifier).
+  set onClick(void Function(String payload)? handler);
 }
 
-/// Shows nothing (desktop today).
+/// Shows nothing (tests, platforms without one).
 class NoSystemNotifications implements SystemNotifications {
   const NoSystemNotifications();
 
   @override
-  Future<void> show({required String title, required String body, String tag = ''}) async {}
+  Future<void> show({required String title, required String body, String tag = '', String payload = ''}) async {}
+
+  @override
+  set onClick(void Function(String payload)? handler) {}
 }

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

@@ -0,0 +1,19 @@
+/// Where the app window stands ([ShellPort.watchActivity]): auto sit-out
+/// and the Notifier (system notifications while it is not focused) read
+/// it. Pure Dart.
+enum WindowActivity {
+  /// The window has the keyboard focus.
+  focused,
+
+  /// Shown, but another window has the focus.
+  unfocused,
+
+  /// Minimised to the taskbar.
+  minimised,
+
+  /// Hidden (closing, or a platform that hides instead of minimising).
+  hidden;
+
+  /// Not in front of the user: notices go out as system notifications.
+  bool get background => this != focused;
+}