Add embedded audio/subtitle track selection for multi-track files

Files with multiple embedded tracks (e.g. MKV from media sources or
downloads) previously exposed none of them: mpv's track-list was never
read, aid was never set, and sid was only ever no/auto. The quality
selector showed no Audio or Subtitles tab for such files.

MPVClient now observes track-list/aid/sid and delivers a coalesced,
leniently decoded [MPVTrack] snapshot; selection state is derived from
the reported "selected" flags. Embedded tracks are switched live via
aid/sid (no reload), surfaced in the existing Audio/Subtitles sections
alongside external captions on iOS, tvOS and macOS. External sub-add/
audio-add tracks are filtered out to avoid double-listing. User picks
are sticky across same-video reloads (quality switch, audio mode,
retries) and preferred audio/subtitle languages auto-select a matching
embedded track once per load, with external captions taking precedence.

Yattee/Views/Player/MPVVideoView.swift

@@ -261,6 +261,16 @@ struct MPVVideoView: View {
                 Task {
                     await playerService.selectStreamManually(stream, audioStream: audioStream)
                 }
+            },
+            embeddedAudioTracks: playerService.embeddedAudioTracks,
+            embeddedSubtitleTracks: playerService.embeddedSubtitleTracks,
+            currentEmbeddedAudioTrackID: playerService.selectedEmbeddedAudioTrackID,
+            currentEmbeddedSubtitleTrackID: playerService.selectedEmbeddedSubtitleTrackID,
+            onEmbeddedAudioTrackSelected: { trackID in
+                playerService.selectEmbeddedAudioTrack(trackID)
+            },
+            onEmbeddedSubtitleTrackSelected: { trackID in
+                playerService.selectEmbeddedSubtitleTrack(trackID)
             }
         )
         #elseif os(macOS)