CI runs the suite under -race, which the local `make test` does not, so
this only showed up there: 230 specs passed and the detector still
failed the run.
The drain-pools spec started Run and never waited for it, so pool
goroutines outlived the spec and raced the config snapshot Ginkgo
restores on cleanup. It now cancels, unparks the blocked lookups and
waits for Run to return.
Two test doubles also had to become concurrency-safe, since the spec is
the first to resolve several artists at once: fakeImageAgent's call
counters, and MockAlbumRepo.GetAll, which records the last query options
on a read path. MockDataStore's lazy accessors get the same treatment —
only MediaFile was guarded before, and two pools now reach them
concurrently. ArtworkQueue takes an unlocked helper for its internal
Artwork call, since repoMu is not reentrant.
73519898eb