Addresses the reported behavior where tracks marked available offline
still buffered from Qobuz after the v1.2.2 upgrade. Three layers:
1. **Snapshot / restore stream-first-track.** offline_settings gains a
new nullable column pre_offline_stream_first_track (SQLite ALTER
migration). v2_set_manual_offline now coordinates with
AudioSettingsState: entering offline mode stashes the user's current
stream_first_track preference and forces it to false; exiting
restores the snapshot. User's preference survives the round-trip
even across app restarts.
2. **Explicit offline refusal.** v2_play_track now takes
OfflineState, reads manual_offline_mode up front, and — when every
local cache miss has been exhausted — returns a new
RuntimeError::TrackNotAvailableOffline instead of silently reaching
for the network. Low-quality offline hits still play (better than
nothing). The playback path also masks stream_first_enabled while
offline as a belt-and-suspenders defense.
3. **Cache-miss visibility.** Every call site that consults the
offline cache DB now logs [V2/CACHE STALE] at warn level when the
DB says a track is cached but the filesystem path is missing. This
made the issue #279 behavior invisible; the orphan entries from
per-user isolation migration (aab3e6764) are now diagnosable from
logs.
Frontend:
- playbackService surfaces TrackNotAvailableOffline as a toast ('…
isn't saved for offline playback') instead of the generic error
- SettingsView listens for a new audio-settings-changed event so the
stream-first-track toggle in the UI flips when the offline toggle
mutates it
- i18n key offline.trackNotAvailableOffline added to all 5 locales
cc
vicrodh
808b9db0db