fix(android): guard desktop fullscreen calls

lib/screens/video_player/parts/companion_remote.dart

@@ -102,7 +102,7 @@ extension _VideoPlayerCompanionRemoteMethods on VideoPlayerScreenState {
   void _cycleAudioTrack() => _trackManager?.cycleAudioTrack();
 
   Future<void> _toggleFullscreen() async {
-    if (PlatformDetector.isMobile(context)) return;
+    if (!PlatformDetector.isDesktopOS()) return;
     await FullscreenStateManager().toggleFullscreen();
   }
 }

lib/services/fullscreen_state_manager.dart

@@ -28,6 +28,8 @@ class FullscreenStateManager extends ChangeNotifier with WindowListener {
 
   /// Toggle fullscreen state, handling maximized-to-fullscreen transition on Windows/Linux
   Future<void> toggleFullscreen() async {
+    if (!PlatformDetector.isDesktopOS()) return;
+
     if (Platform.isMacOS) {
       final isCurrentlyFullscreen = await MacOSWindowService.isFullscreen();
       if (isCurrentlyFullscreen) {
@@ -62,6 +64,8 @@ class FullscreenStateManager extends ChangeNotifier with WindowListener {
 
   /// Enter fullscreen, preserving maximized state on Windows/Linux for restoration on exit.
   Future<void> enterFullscreen() async {
+    if (!PlatformDetector.isDesktopOS()) return;
+
     if (Platform.isMacOS) {
       await MacOSWindowService.enterFullscreen();
     } else if (Platform.isWindows) {
@@ -77,6 +81,8 @@ class FullscreenStateManager extends ChangeNotifier with WindowListener {
 
   /// Exit fullscreen, restoring maximized state if needed
   Future<void> exitFullscreen() async {
+    if (!PlatformDetector.isDesktopOS()) return;
+
     if (Platform.isMacOS) {
       await MacOSWindowService.exitFullscreen();
     } else if (Platform.isWindows) {

lib/widgets/video_controls/parts/visibility.dart

@@ -293,14 +293,14 @@ extension _PlexVideoControlsVisibilityMethods on _PlexVideoControlsState {
   }
 
   Future<void> _toggleFullscreen() async {
-    if (!PlatformDetector.isMobile(context)) {
-      await FullscreenStateManager().toggleFullscreen();
-    }
+    if (!PlatformDetector.isDesktopOS()) return;
+    await FullscreenStateManager().toggleFullscreen();
   }
 
   /// Exit fullscreen if the window is actually fullscreen (async check).
   /// Used by ESC handler on Windows/Linux to avoid relying on _isFullscreen flag.
   Future<void> _exitFullscreenIfNeeded() async {
+    if (!Platform.isWindows && !Platform.isLinux) return;
     if (await windowManager.isFullScreen()) {
       await FullscreenStateManager().exitFullscreen();
     }
@@ -318,14 +318,14 @@ extension _PlexVideoControlsVisibilityMethods on _PlexVideoControlsState {
 
   /// Toggle always-on-top window mode (desktop only)
   Future<void> _toggleAlwaysOnTop() async {
-    if (!PlatformDetector.isMobile(context)) {
-      final newValue = !_isAlwaysOnTop;
-      await windowManager.setAlwaysOnTop(newValue);
-      if (!mounted) return;
-      _setControlsState(() {
-        _isAlwaysOnTop = newValue;
-      });
-    }
+    if (!PlatformDetector.isDesktopOS()) return;
+
+    final newValue = !_isAlwaysOnTop;
+    await windowManager.setAlwaysOnTop(newValue);
+    if (!mounted) return;
+    _setControlsState(() {
+      _isAlwaysOnTop = newValue;
+    });
   }
 
   /// Show controls and optionally focus play/pause on keyboard input (desktop only)