Headline of S4. "Shuffle all" is always present (home app-bar
shuffle icon); the pool degrades with reachability:
- online → GET /api/library/shuffle?limit=N (new): N random
library tracks server-side, per-user quarantine filtered
(ListRandomTracksForUser, ORDER BY random()).
- offline → ShuffleSource shuffles the whole local cache index
(audio_cache_index ∩ cached_tracks, names from cached_artists/
albums) — a UNION over liked AND recently-played, since the
two-bucket split is storage-only and never filters playback.
Offline gating: refreshable (singleton) system playlists need the
live build/shuffle endpoints, so their tile play is disabled when
offlineProvider is true — Shuffle all is the offline path. User
playlists still play from cache.
playlist_card now reads offlineProvider in build → wrapped the
direct-render widget test in ProviderScope (offlineProvider is
smoke-safe from S1: tracked timers, no connectivity mount).
S4b (offline Recently-played / Liked browsable surfaces over the
cache index) next.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
