Closes#7
mpv only turns on a subtitle that is flagged default or matches `slang`, so releases like VisionQuest (Russian dub by default, ru/ru/en subtitles, none flagged) open with subtitles off, which also disabled **Translate subtitle**.
- New `TrackSelection` helpers in `qtpotato_core` with unit tests.
- On file load: audio follows *Preferred languages* (Playback settings); subtitle follows *Preferred languages* (Subtitles settings), else keeps mpv's choice, else (new *Turn on a subtitle when none matches*, on by default) picks a full text subtitle in the system language, then English, then the audio language, then the default/first track.
- Translate is enabled whenever the file has a text subtitle; with none or a bitmap subtitle shown it translates the best text track (English first).
Verified in the real app on VisionQuest S01E01: subtitle 3 (en) is selected on open; with audio set to `en` and auto-select off, audio switches to track 7, subtitle stays off and Translate stays enabled with the English source.
Reviewed-on: #12
Co-authored-by: Tri Vo Khac <git@trivk.dev>
mpvqt renders without disabling MPV_RENDER_PARAM_BLOCK_FOR_TARGET_TIME, so each new video frame blocks the Qt Quick render thread for up to video-timing-offset (50 ms). Animations over a playing video (playlist slide-in) stuttered; paused video was smooth. Set video-timing-offset=0.
Measured offscreen while toggling the playlist during playback: worst frame 35–39 ms before, 17–21 ms after.
Reviewed-on: #6
Co-authored-by: Tri Vo Khac <git@trivk.dev>
Apply glossary edits directly to translated subtitles and reload the active track. Keep terms with their originating episode, preserve existing translations, and clear stale episode groups with glossary entries.
tri
