Add a play overlay button shown on cover art hover that inserts the
track into the queue right after the current track and jumps to it,
so it takes priority over what's already queued. Replaces the
double-click-to-play interaction with a new playNow queue action.
Three tiers of offline support, all scoped to the active backend's
localStorage namespace (mirroring the auth slice):
Tier 1 — persist client state. queue + player slices are saved (queue
entries/index/source; player track/position/volume/repeat/shuffle) and
rehydrated on load, so a reload with no backend restores where the user
left off. Playback never auto-resumes (browsers block autoplay). Retires
the DEMO_QUEUE and isQueueOpen:true stubs.
Tier 2 — persist the RTK Query cache. Last-seen library/albums/artists
are snapshotted (fulfilled queries only) and replayed via RTKQ's
extractRehydrationInfo at startup, so the library renders read-only when
the backend is down. ConnectionStatus tooltip flags cached data offline.
No server data is copied into a slice — the cache feeds itself back.
Tier 3 — service worker audio + cover cache (PWA). Audio streams are
cached keyed by content id (token stripped), range-aware (synthetic 206
slicing), with a 500MB LRU cap, so already-played tracks play fully
offline. Cover art uses stale-while-revalidate in its own bounded cache.
Module worker (ESM); pure helpers split into sw-core.js and unit-tested.
Web app manifest enables "Install app". Player source badge now reflects
real cached state.
tsc clean, lint clean, 19 new tests pass, production build verified.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Senko-san
olly