fix(anime): clean up discarded queued subtitles in background

- Let queued episode discard return before subtitle preparation finishes
- Remove the redundant queued subtitle loading command

src/anime-bridge/mpv-playback.test.ts

@@ -65,7 +65,6 @@ test('queued playback carries file-local title and language preferences into mpv
     ),
   );
   assert.deepEqual(buildQueuedPlaybackCommands(options), [
-    ['script-message', 'subminer-managed-subtitles-loading'],
     [
       'loadfile',
       'https://video.example/episode.m3u8',

src/anime-bridge/mpv-playback.ts

@@ -126,10 +126,7 @@ export function buildPlaybackCommands(options: BuildPlaybackOptions): MpvCommand
 
 /** Append a fully resolved stream without replacing the file playing now. */
 export function buildQueuedPlaybackCommands(options: BuildPlaybackOptions): MpvCommand[] {
-  return [
-    ['script-message', 'subminer-managed-subtitles-loading'],
-    ['loadfile', options.stream.url, 'append-play', -1, buildQueuedLoadfileOptions(options)],
-  ];
+  return [['loadfile', options.stream.url, 'append-play', -1, buildQueuedLoadfileOptions(options)]];
 }
 
 /**