refactor: convert from Android TV to phone/tablet mode
- Replace Theme.Leanback with Theme.AppCompat.DayNight.NoActionBar
- Remove leanback dependencies (leanback, leanback-preference)
- Remove LEANBACK_LAUNCHER, leanback feature, banner from manifest
- PlayerActivity: replace D-pad with touch controls (click to toggle episodes, close button)
- SearchFragment: adaptive grid (3 cols phone / 5 cols tablet), remove focus-based history toggle
- Fix deprecated adapterPosition -> bindingAdapterPosition
153b555d52