Shared artwork HTTP client gains the missing 10s total timeout (half-up
networks could pin the 16-permit semaphore). fetch_cached_http short-
circuits while offline: disk hits serve, misses return the placeholder
immediately with zero network and no negative caching. Now-playing meta
resolves MPRIS art to a cached file:// URL (or none) instead of an
unfetchable https URL while offline; system notifications skip their
blocking artwork download offline via an injected flag, keeping
qbz-media-controls frontend-agnostic.
Part of offline-mode slice 3; main.rs wiring rides the slice-3 wiring
commit.
cc
vicrodh
dee85faadb