Entity-level artwork queries now take a typed model.Kind instead of a bare
prefix string. GetItemArtwork, DeleteForItem(s), GetInfoForItems,
EnqueueStaleAbsent, hydrateItemImages, enqueueBackfillKind and artwork.Refresh
convert to the prefix string only at the two real boundaries: the SQL
item_kind column (kind.Prefix() inside each repo) and external string inputs
(a new model.ParseKind for the nativeapi URL param, which also validates it).
The Backfill/stale-absent kind slices, the resolve.go dispatch switch, and the
kind→resource / kind→table lookup maps now use the Kind vars directly. The
queue lifecycle methods (MarkFailed/Delete*) keep string kinds — they operate
on a dequeued item's raw ItemKind column, which stays a string field, always
populated via kind.Prefix().
Removes every bare "al"/"ar"/… prefix literal from non-test code (27 -> 0);
behavior is unchanged.
Relocate the image-upload service from core to core/artwork as
artwork.Uploader, co-locating it with the resolver/worker/serving that own
the artwork state it invalidates. MaxImageUploadSize moves too — its only
callers are the two image-upload handlers — which lets core/image_upload.go
be deleted entirely.
Extract the shared "clear resolved state + re-queue at Bump" invalidation
into artwork.Refresh and fold nativeapi's refreshArtwork handler onto it,
removing the duplicated DeleteForItem+Enqueue block that had drifted into
three places.
The wire provider moves from core's set to artwork's; the
playlists.ImageUploadService binding moves to the top-level injector so
core/artwork stays unaware of playlists. Behavior is unchanged.
