An episode that ends while backgrounded in audio-only mode advances in the
backend, but player_exit_background_audio returned only a position, so the
video page reloaded the episode it was mounted with -- the previous one, at
the new episode's timestamp.
The command now returns BackgroundAudioResume { itemId, positionSeconds }.
planHandoffReturn yields "other-item" when the id differs from the mounted
one, and the player page navigates to that episode with resumeAt=<seconds>,
marking the outgoing episode watched and suppressing its stale stop report.
TRACES: UR-040, UR-023 | DR-296 | UT-265, UT-266
Hand video playback off to a native audio-only stream when the app is
backgrounded or locked, with no on-device video decode (UR-040). Adds
player_enter/exit_background_audio commands, an audio-only stream URL
for video items across the repository layer, and the frontend handoff
state machine wired into VideoPlayer. Includes accompanying
repository/offline/player refactoring and regenerates the traceability
matrix.
dtourolle