fix(lifecycle): guard async state updates

lib/mixins/item_updatable.dart

@@ -26,6 +26,7 @@ mixin ItemUpdatable<T extends StatefulWidget> on State<T> {
       if (serverId == null) return;
       final updatedItem = await context.tryGetMediaClientForServer(serverId)?.fetchItem(itemId);
       if (updatedItem != null) {
+        if (!mounted) return;
         setState(() {
           updateItemInLists(itemId, updatedItem);
         });

lib/screens/discover_screen.dart

@@ -394,7 +394,7 @@ class _DiscoverScreenState extends State<DiscoverScreen>
       _heroController.animateToPage(nextPage, duration: const Duration(milliseconds: 500), curve: Curves.easeInOut);
       // Wait for page transition to complete before resetting progress
       Future.delayed(const Duration(milliseconds: 500), () {
-        if (!_isAutoScrollPaused) {
+        if (mounted && !_isAutoScrollPaused) {
           _startIndicatorProgress();
         }
       });
@@ -402,11 +402,16 @@ class _DiscoverScreenState extends State<DiscoverScreen>
   }
 
   void _startIndicatorProgress() {
+    if (!mounted) return;
     _indicatorTimer?.cancel();
     _indicatorProgress.value = 0.0;
     final totalSteps = _heroAutoScrollDuration.inMilliseconds ~/ _indicatorUpdateInterval.inMilliseconds;
     int step = 0;
     _indicatorTimer = Timer.periodic(_indicatorUpdateInterval, (timer) {
+      if (!mounted) {
+        timer.cancel();
+        return;
+      }
       step++;
       _indicatorProgress.value = (step / totalSteps).clamp(0.0, 1.0);
       if (step >= totalSteps) {

lib/screens/livetv/tabs/guide_tab.dart

@@ -705,6 +705,7 @@ class GuideTabState extends State<GuideTab> with MountedSetStateMixin {
         }),
       ],
     ).then((value) {
+      if (!mounted) return;
       if (value == null) {
         _guideFocusNode.requestFocus();
         return;

lib/screens/video_player_screen.dart

@@ -29,6 +29,7 @@ import '../models/livetv_capture_buffer.dart';
 import '../models/livetv_channel.dart';
 import '../models/transcode_quality_preset.dart';
 import '../media/media_source_info.dart';
+import '../mixins/mounted_set_state_mixin.dart';
 import '../providers/download_provider.dart';
 import '../providers/multi_server_provider.dart';
 import '../providers/playback_state_provider.dart';
@@ -213,7 +214,7 @@ class VideoPlayerScreen extends StatefulWidget {
   State<VideoPlayerScreen> createState() => VideoPlayerScreenState();
 }
 
-class VideoPlayerScreenState extends State<VideoPlayerScreen> with WidgetsBindingObserver {
+class VideoPlayerScreenState extends State<VideoPlayerScreen> with WidgetsBindingObserver, MountedSetStateMixin {
   static const int _liveEdgeThresholdSeconds = 5;
 
   // Track the currently active video to guard against duplicate navigation
@@ -1131,7 +1132,7 @@ class VideoPlayerScreenState extends State<VideoPlayerScreen> with WidgetsBindin
     await _navigateToEpisode(metadata);
   }
 
-  void _setPlayerState(VoidCallback fn) => setState(fn);
+  void _setPlayerState(VoidCallback fn) => setStateIfMounted(fn);
 
   bool _isSwitchingChannel = false;
 

lib/watch_together/screens/watch_together_screen.dart

@@ -347,12 +347,12 @@ class _NotInSessionViewState extends State<_NotInSessionView> with MountedSetSta
     if (name == null || !mounted) return;
 
     await RecentRoomsService.renameRoom(room.code, name.isEmpty ? null : name);
-    setState(() => _recentRooms = RecentRoomsService.getRecentRooms());
+    setStateIfMounted(() => _recentRooms = RecentRoomsService.getRecentRooms());
   }
 
   Future<void> _removeRoom(RecentRoom room) async {
     await RecentRoomsService.removeRoom(room.code);
-    setState(() => _recentRooms = RecentRoomsService.getRecentRooms());
+    setStateIfMounted(() => _recentRooms = RecentRoomsService.getRecentRooms());
   }
 }
 

lib/widgets/video_controls/desktop_video_controls.dart

@@ -336,6 +336,7 @@ class DesktopVideoControlsState extends State<DesktopVideoControls> {
     widget.onContentStripVisibilityChanged?.call(true);
 
     WidgetsBinding.instance.addPostFrameCallback((_) {
+      if (!mounted) return;
       _contentStripKey.currentState?.requestInitialFocus();
     });
   }
@@ -349,6 +350,7 @@ class DesktopVideoControlsState extends State<DesktopVideoControls> {
 
     // Return focus to the last focused button (or play/pause as fallback)
     WidgetsBinding.instance.addPostFrameCallback((_) {
+      if (!mounted) return;
       final target = _lastFocusedButtonNode;
       if (target != null && target.context != null) {
         target.requestFocus();

lib/widgets/video_controls/parts/playback_input.dart

@@ -167,6 +167,7 @@ extension _PlexVideoControlsPlaybackInputMethods on _PlexVideoControlsState {
 
     final delta = Duration(seconds: isForward ? _seekTimeSmall : -_seekTimeSmall);
     await _seekByOffset(delta);
+    if (!mounted) return;
 
     // Refresh feedback (extends timer, updates display)
     _showSkipFeedback(isForward: isForward);
@@ -181,6 +182,7 @@ extension _PlexVideoControlsPlaybackInputMethods on _PlexVideoControlsState {
 
     final delta = Duration(seconds: isForward ? _seekTimeSmall : -_seekTimeSmall);
     await _seekByOffset(delta);
+    if (!mounted) return;
 
     _showSkipFeedback(isForward: isForward);
 

lib/widgets/video_controls/parts/track_controls.dart

@@ -34,8 +34,9 @@ extension _PlexVideoControlsTrackMethods on _PlexVideoControlsState {
         shaderService
             .applyPreset(ShaderPreset.none)
             .then((_) {
+              if (!mounted) return;
               // ignore: no-empty-block - setState triggers rebuild to reflect disabled shader
-              if (mounted) _setControlsState(() {});
+              _setControlsState(() {});
               widget.onShaderChanged?.call();
             })
             .catchError((Object e, StackTrace st) {
@@ -54,9 +55,10 @@ extension _PlexVideoControlsTrackMethods on _PlexVideoControlsState {
         shaderService
             .applyPreset(targetPreset)
             .then((_) {
+              if (!mounted) return;
               shaderProvider.setCurrentPreset(targetPreset);
               // ignore: no-empty-block - setState triggers rebuild to reflect restored shader
-              if (mounted) _setControlsState(() {});
+              _setControlsState(() {});
               widget.onShaderChanged?.call();
             })
             .catchError((Object e, StackTrace st) {

lib/widgets/video_controls/parts/visibility.dart

@@ -344,6 +344,7 @@ extension _PlexVideoControlsVisibilityMethods on _PlexVideoControlsState {
 
     if (requestFocus) {
       WidgetsBinding.instance.addPostFrameCallback((_) {
+        if (!mounted) return;
         _desktopControlsKey.currentState?.requestPlayPauseFocus();
       });
     } else {
@@ -372,6 +373,7 @@ extension _PlexVideoControlsVisibilityMethods on _PlexVideoControlsState {
     _startHideTimer();
 
     WidgetsBinding.instance.addPostFrameCallback((_) {
+      if (!mounted) return;
       _desktopControlsKey.currentState?.requestTimelineFocus();
     });
   }

lib/widgets/video_controls/sheets/video_settings_sheet.dart

@@ -798,8 +798,9 @@ class _VideoSettingsSheetState extends State<VideoSettingsSheet> {
                 }
                 await widget.shaderService!.applyPreset(preset);
                 await shaderProvider.setPreset(preset);
+                if (!context.mounted) return;
                 widget.onShaderChanged?.call();
-                if (context.mounted) OverlaySheetController.of(context).close();
+                OverlaySheetController.of(context).close();
               },
             );
           },
@@ -826,6 +827,7 @@ class _VideoSettingsSheetState extends State<VideoSettingsSheet> {
         }
         await widget.shaderService!.applyPreset(preset);
         await shaderProvider.setPreset(preset);
+        if (!mounted) return;
         widget.onShaderChanged?.call();
       }
 
@@ -846,7 +848,7 @@ class _VideoSettingsSheetState extends State<VideoSettingsSheet> {
     // If the deleted shader is active, clear it from the player first
     if (widget.shaderService!.currentPreset.id == preset.id) {
       await widget.shaderService!.applyPreset(ShaderPreset.none);
-      widget.onShaderChanged?.call();
+      if (mounted) widget.onShaderChanged?.call();
     }
 
     await shaderProvider.deleteCustomShader(preset);

lib/widgets/video_controls/video_controls.dart

@@ -22,6 +22,7 @@ import '../../services/pip_service.dart';
 import 'package:window_manager/window_manager.dart';
 
 import '../../mixins/settings_effect_mixin.dart';
+import '../../mixins/mounted_set_state_mixin.dart';
 import '../../mpv/mpv.dart';
 import '../overlay_sheet.dart';
 import '../../focus/dpad_navigator.dart';
@@ -337,7 +338,8 @@ class PlexVideoControls extends StatefulWidget {
   State<PlexVideoControls> createState() => _PlexVideoControlsState();
 }
 
-class _PlexVideoControlsState extends State<PlexVideoControls> with WindowListener, SettingsEffectMixin {
+class _PlexVideoControlsState extends State<PlexVideoControls>
+    with WindowListener, SettingsEffectMixin, MountedSetStateMixin {
   bool _showControls = true;
   bool _forceShowControls = false;
   bool _isLoadingExtras = false;
@@ -501,7 +503,7 @@ class _PlexVideoControlsState extends State<PlexVideoControls> with WindowListen
     });
   }
 
-  void _setControlsState(VoidCallback fn) => setState(fn);
+  void _setControlsState(VoidCallback fn) => setStateIfMounted(fn);
 
   @override
   void dispose() {