A Plex queue track's artwork was file://-prefixed onto its raw /library/ thumb
path, breaking the cover on all three surfaces. Approach (b) from the funnel
review: keep the raw path in QueueTrack.artwork_url (token never persisted) and
resolve to a fresh tokenized PlexThumb from live plex_settings creds at each
surface.
- qbz-models: additive QueueTrack::artwork_ref_with_plex(base_url, token) — a raw
/library or /photo path + creds => ArtworkRef::PlexThumb, else falls back to
artwork_ref() (http/file:// unchanged). 4 regression tests.
- playback.rs: local_queue_track keeps the raw path for Plex rows (no file://
poison); refresh_now_playing_meta uses artwork_ref_with_plex -> fixes the
now-playing bar, MPRIS (to_mpris_url), and the desktop notification.
- queue.rs: load_artwork threads creds + a PlexThumb branch for the queue panel.
- Local/Qobuz/ephemeral artwork byte-for-byte unchanged.
cc