Media files are never enqueued — the scanner drops their state without
queueing them and the recheck kinds exclude them — so an unresolved
track keeps an empty ImageHash and SongToBaseItem always fell through to
AlbumPrimaryImageTag. Finamp then asks for the album image, nothing ever
requests mf-, and the read-through that resolves the track never fires:
the own-cover branch was unreachable for Jellyfin-only users.
An eligible, unresolved, not-known-absent track now advertises its id as
the Primary tag, which is what makes the client ask. The request serves
the embedded art and queues the track so the worker persists a real
hash. No blurhash is sent, since none exists yet and a fake would be
cached against that tag forever.
Serving gains the album fallback that made this safe to advertise: an
eligible track whose frame will not extract now falls back the way
CoverArtID does instead of answering with a placeholder.
Reported by Codex on #5847.
6f93fa3141