After skipping through already-buffered tracks the player stays READY, so
onPlaybackStateChanged never fires and syncState() isn't re-called; ctrl.duration
was TIME_UNSET(→0) at the transition, leaving state.durationMs stuck at 0. The
seek bar then computed fraction*0 = 0 and snapped playback to the start every time
(or to a stale value → "only 10s"). Restarting the app re-read the real duration,
which is why it recovered.
Fix: durationMs now self-heals — the 500ms ticker refreshes it too, and
resolveDurationMs() falls back to the current song's known duration while
ctrl.duration is still unset. Also record the Erkunden swipe-between-tabs idea.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>