The Redis media:status key was only rewritten after a command received via
Redis. When the last track ended naturally (AudioPlayer Idle -> advanceQueue
with an empty queue), currentTrackItem was cleared but the status key was not
persisted — so the backend's cached status and the frontend's 10s polling
stayed stuck showing the finished track as 'playing' forever.
Wire a media-status sink (commandHandler provides the real redisPub to
MediaHandler) and re-publish status after auto-advance, so natural track end
updates the UI.