fix: persist aspect ratio and shader settings

Closes #602, closes #603

lib/screens/video_player_screen.dart

@@ -1106,6 +1106,8 @@ class VideoPlayerScreenState extends State<VideoPlayerScreen> with WidgetsBindin
             player: player!,
             availableVersions: _availableVersions,
             selectedMediaIndex: widget.selectedMediaIndex,
+            initialBoxFitMode: settingsService.getDefaultBoxFitMode(),
+            onBoxFitModeChanged: (mode) => settingsService.setDefaultBoxFitMode(mode),
           );
           // Update video filter once dimensions are available
           _videoFilterManager!.updateVideoFilter();
@@ -1265,15 +1267,18 @@ class VideoPlayerScreenState extends State<VideoPlayerScreen> with WidgetsBindin
     }
   }
 
-  /// Apply the saved shader preset on playback start
+  /// Apply the saved shader preset on playback start.
+  /// Reads directly from SettingsService (synchronous SharedPreferences) to
+  /// avoid a race with ShaderProvider's async initialization.
   Future<void> _applySavedShaderPreset() async {
     if (_shaderService == null || !_shaderService!.isSupported) return;
 
     try {
-      final shaderProvider = context.read<ShaderProvider>();
-      final preset = shaderProvider.savedPreset;
+      final settings = await SettingsService.getInstance();
+      final presetId = settings.getGlobalShaderPreset();
+      final preset = ShaderPreset.fromId(presetId) ?? ShaderPreset.none;
       await _shaderService!.applyPreset(preset);
-      shaderProvider.setCurrentPreset(preset);
+      context.read<ShaderProvider>().setCurrentPreset(preset);
     } catch (e) {
       appLogger.d('Could not apply shader preset', error: e);
     }

lib/services/settings_service.dart

@@ -70,6 +70,7 @@ class SettingsService extends BaseSharedPreferencesService {
   static const String _keyMatchContentFrameRate = 'match_content_frame_rate';
   static const String _keyTunneledPlayback = 'tunneled_playback';
   static const String _keyDefaultPlaybackSpeed = 'default_playback_speed';
+  static const String _keyDefaultBoxFitMode = 'default_box_fit_mode';
   static const String _keyAutoPlayNextEpisode = 'auto_play_next_episode';
   static const String _keyUseExoPlayer = 'use_exoplayer';
   static const String _keyAlwaysKeepSidebarOpen = 'always_keep_sidebar_open';
@@ -1041,6 +1042,15 @@ class SettingsService extends BaseSharedPreferencesService {
     return prefs.getDouble(_keyDefaultPlaybackSpeed) ?? 1.0; // Default: normal speed
   }
 
+  // Default BoxFit Mode (0=contain, 1=cover, 2=fill)
+  Future<void> setDefaultBoxFitMode(int mode) async {
+    await prefs.setInt(_keyDefaultBoxFitMode, mode.clamp(0, 2));
+  }
+
+  int getDefaultBoxFitMode() {
+    return prefs.getInt(_keyDefaultBoxFitMode) ?? 0; // Default: contain
+  }
+
   // Auto-Play Next Episode
   Future<void> setAutoPlayNextEpisode(bool enabled) async {
     await prefs.setBool(_keyAutoPlayNextEpisode, enabled);
@@ -1244,6 +1254,7 @@ class SettingsService extends BaseSharedPreferencesService {
       prefs.remove(_keyMatchContentFrameRate),
       prefs.remove(_keyTunneledPlayback),
       prefs.remove(_keyDefaultPlaybackSpeed),
+      prefs.remove(_keyDefaultBoxFitMode),
       prefs.remove(_keyAutoPlayNextEpisode),
       prefs.remove(_keyUseExoPlayer),
       prefs.remove(_keyAlwaysKeepSidebarOpen),

lib/services/video_filter_manager.dart

@@ -21,7 +21,7 @@ class VideoFilterManager {
   final int selectedMediaIndex;
 
   /// BoxFit mode state: 0=contain (letterbox), 1=cover (fill screen), 2=fill (stretch)
-  int _boxFitMode = 0;
+  int _boxFitMode;
 
   /// Store the boxFitMode before entering PiP so it can be restored
   int? _prePipBoxFitMode;
@@ -41,7 +41,10 @@ class VideoFilterManager {
   /// Debounced video filter update with leading edge execution
   late final Debounce _debouncedUpdateVideoFilter;
 
-  VideoFilterManager({required this.player, required this.availableVersions, required this.selectedMediaIndex}) {
+  /// Callback invoked when boxFitMode changes, for external persistence
+  final void Function(int mode)? onBoxFitModeChanged;
+
+  VideoFilterManager({required this.player, required this.availableVersions, required this.selectedMediaIndex, int initialBoxFitMode = 0, this.onBoxFitModeChanged}) : _boxFitMode = initialBoxFitMode {
     _debouncedUpdateVideoFilter = debounce(
       updateVideoFilter,
       const Duration(milliseconds: 50),
@@ -59,6 +62,7 @@ class VideoFilterManager {
   /// Cycle through BoxFit modes: contain → cover → fill → contain (for button)
   void cycleBoxFitMode() {
     _boxFitMode = (_boxFitMode + 1) % 3;
+    onBoxFitModeChanged?.call(_boxFitMode);
     updateVideoFilter();
   }
 
@@ -73,6 +77,7 @@ class VideoFilterManager {
   /// Toggle between contain and cover modes only (for pinch gesture)
   void toggleContainCover() {
     _boxFitMode = _boxFitMode == 0 ? 1 : 0;
+    onBoxFitModeChanged?.call(_boxFitMode);
     updateVideoFilter();
   }