fix(player): keep hidden and cycled subtitles off in the next episode

Episode navigation carries the subtitle choice this screen has committed, so
a way of turning subtitles off that the screen never sees is undone by the
next episode.

ExoPlayer has no renderer-level visibility switch, so the player's hide
toggle is emulated by deselecting the track. That emulation lasted until the
next selection: the automatic pass after an episode change put subtitles
straight back on screen while the toggle still read "hidden", and un-hiding
then restored a track id belonging to the episode that had already ended.
Hiding is now sticky across media opens the way mpv's global sub-visibility
is, selections made while hidden become what un-hiding restores, and the
toggle no longer refuses to restore because the hidden track reads as Off.

Cycling subtitles over the native track list — downloads, and items whose
server exposes no subtitle rows — went straight to the track manager, which
owns the player selection and the server write-back but not the committed
choice. The screen records the cycled track now.

lib/screens/video_player/parts/companion_remote.dart

@@ -109,7 +109,20 @@ extension _VideoPlayerCompanionRemoteMethods on VideoPlayerScreenState {
       if (!_subtitleCycleDrainActive) unawaited(_drainSubtitleCycles());
       return;
     }
-    _trackManager?.cycleSubtitleTrack();
+    _cycleSubtitleTrackNatively();
+  }
+
+  /// Cycle through the native track list, for playback with no source
+  /// catalog to advance through (downloads, and items whose server exposes no
+  /// subtitle rows).
+  ///
+  /// The manager owns the selection and the server write-back; the committed
+  /// choice is this screen's, and the episode carry-over reads it, so a cycle
+  /// that lands on Off has to be recorded here or the next episode inherits
+  /// the choice this one started with.
+  void _cycleSubtitleTrackNatively() {
+    final cycled = _trackManager?.cycleSubtitleTrack();
+    if (cycled != null) _rememberNativeSubtitleSelection(cycled);
   }
 
   Future<void> _drainSubtitleCycles() async {
@@ -127,7 +140,7 @@ extension _VideoPlayerCompanionRemoteMethods on VideoPlayerScreenState {
         if (_isOfflinePlayback || sourceTracks.isEmpty) {
           _pendingSubtitleCycleCount -= advances;
           for (var i = 0; i < advances; i++) {
-            _trackManager?.cycleSubtitleTrack();
+            _cycleSubtitleTrackNatively();
           }
           continue;
         }