c396b673ac
Reads MINSTREL_SOURCE_KEY from the current MediaItem's extras and
projects it as PlayerUiState.currentSource. PlayEventsReporter
needs this to tag plays with their originating system playlist
('for_you'/'discover'/'radio:<id>') so the server advances the
right rotation.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>