Fix Android TV quality switch overlay bug and respect default quality

[xayron]

What changed

This commit resolves two playback issues:

1. Android TV Stuttering/Overlay Bug on Quality Switch: By default, PlayerView retains the last decoded frame on the SurfaceView when the player is stopped/reset. On Android TV's hardware overlay, this caused the new video source to render as a smaller overlay on top of the stale, stuttering frame from the previous source. Added track selection override resets loading a new source to prevent previous bitrate caps or audio track choices from bleeding into the new decoder pipeline.

2. Global Default Quality (e.g., 720p) Ignored on Non-HLS Streams: Previously, the player ignored user preferences and hardcoded the choice to the absolute highest quality.

Checklist

• flutter analyze is clean
• flutter test passes
• Native build still compiles, if I touched android/ or ios/
• I've read and agree to the CLA
• New dependency or third-party code? NOTICE.md updated in this PR
• Used AI tooling? Disclosed per AI_POLICY.md

Screenshots

Before:

After:

[NeighborhoodNerd]

@xayron bump

[xayron]

Hi. Sorry for the delayed response. I will look into your suggestions and try incoprating them. If nothing breaks, will push again with the changes you suggested.

[xayron]

@NeighborhoodNerd made the changes as per your suggestion

[NeighborhoodNerd]

Thanks for the follow-up and for narrowing the track override reset to video-only — that addresses the audio-reset concern.

This branch can't merge cleanly against current main anymore (all 6 files conflict). More importantly, the Dart side overlaps work that landed in 9421b5b: pickDefault now takes preferQuality with resolutionPx + nearest-match logic and tests in test/playback/source_selection_test.dart. Please drop the source_selection.dart changes from this PR rather than reintroducing a parallel pref/qualityRank implementation.

What we'd still like from this PR:

1. Keep the Kotlin Android TV fixes — setKeepContentOnPlayerReset(false) and the stop/clear/clear video overrides before loading a new source in ExoPlayerView.kt and TvPlayerActivity.kt.
2. Wire default quality on the remaining call sites using the existing API, e.g. pickDefault(..., preferQuality: sl<PlaybackPrefs>().defaultQuality) in:
   • player_screen.dart
   • tv_exo_player_screen.dart (both call sites)
   • tv_native_player.dart

Please rebase onto latest main, resolve conflicts keeping our preferQuality implementation, and run flutter analyze + flutter test before pushing (checklist items still open).

Note: the ExoPlayerView.kt changes also affect the phone DRM platform view, not just TV — a quick sanity check there after rebase would be appreciated.

Happy to re-review once rebased.