Locking Down a Single Source of Truth for Playback State

There was a class of inconsistency where the lock screen widget displayed a track title and playback status that did not match the audio actually playing. Common cases included the mini player showing active playback after a lock-screen pause, or the displayed track differing from the one currently heard. The root cause was each UI surface independently maintaining and updating its own playback state.

This work consolidated playback state into a single owner. Rather than the lock screen remote control, mini player, and reels view each writing state directly, a single source now determines current playback state and all UI surfaces reflect it. Processing order was defined so that interleaved audio session and track-loading events resolve to a consistent final state, and verification criteria were established to confirm that ordering holds.

Playback-related screens were updated in parallel. The layout was restructured to surface the current and upcoming track clearly, and moment and inst entries were aligned to appear under consistent criteria across browse and recommendation contexts.

This class of mismatch does not surface in feature checklists, but it directly degrades playback reliability. Binding displayed state and actual audio to the same source was the core objective.