feat: a release catalogue from MusicBrainz; request search asks it directly (M502 #5519)

Minstrel keeps its own record of what artists have released, read from
MusicBrainz, so the wanted list, search and import no longer need Lidarr.

- internal/musicbrainz: searches (artists, release groups, recordings) and
  browses (an artist's release groups; a group's releases with track lists).
  One process-wide pacer at 1.1s, shared with tag enrichment, because
  MusicBrainz's limit is per address. A 503 throttle is retried.
- Migration 0080: mb_artists, mb_release_groups, mb_artist_release_groups
  (a collaboration belongs to each credited artist), mb_releases,
  mb_release_tracks.
- internal/catalogue: Discography and Releases serve the held copy and
  re-read it when older than 7 or 30 days. An unreachable MusicBrainz
  serves the stale copy, marked. An hourly pass re-reads due artists.
- Art for what isn't held comes through /api/catalogue/art from the
  enabled cover-art sources (Cover Art Archive by release group, then the
  name-based sources) and is kept on disk, so the browser never fetches a
  third-party host. A miss is a 404 and the card shows its icon.
- Request search moves from /api/lidarr/search to /api/catalogue/search,
  with the same response shape. Albums are release groups, and "in
  library" matches albums.release_group_mbid. A 10-minute cache absorbs
  search-as-you-type. Discover suggestions point at the art endpoint
  instead of looking up Lidarr.
- Android calls the new path and loads Discover art through ServerImage.
  Installed builds older than this one lose Discover search until they
  update (no compatibility path, rule 22).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/db/queries/catalogue.sql

@@ -0,0 +1,101 @@
+-- The release catalogue read from MusicBrainz (M502 #5519).
+
+-- name: UpsertMBArtist :exec
+INSERT INTO mb_artists (mbid, name, sort_name, disambiguation, artist_type, country)
+VALUES (sqlc.arg(mbid), sqlc.arg(name), sqlc.arg(sort_name), sqlc.arg(disambiguation),
+        sqlc.arg(artist_type), sqlc.arg(country))
+ON CONFLICT (mbid) DO UPDATE SET
+    name           = EXCLUDED.name,
+    sort_name      = EXCLUDED.sort_name,
+    disambiguation = EXCLUDED.disambiguation,
+    artist_type    = EXCLUDED.artist_type,
+    country        = EXCLUDED.country,
+    updated_at     = now();
+
+-- name: GetMBArtist :one
+SELECT * FROM mb_artists WHERE mbid = sqlc.arg(mbid);
+
+-- name: MarkMBArtistDiscographyRefreshed :exec
+UPDATE mb_artists SET discography_refreshed_at = now() WHERE mbid = sqlc.arg(mbid);
+
+-- name: ListMBArtistsDueForRefresh :many
+-- Artists whose discography has never been read, or was read before the
+-- cutoff: never-read first, then oldest first.
+SELECT mbid FROM mb_artists
+WHERE discography_refreshed_at IS NULL OR discography_refreshed_at < sqlc.arg(before)
+ORDER BY discography_refreshed_at NULLS FIRST, mbid
+LIMIT sqlc.arg(max_rows);
+
+-- name: UpsertMBReleaseGroup :exec
+-- Leaves releases_refreshed_at alone: re-reading a discography says nothing
+-- about whether the group's track lists are current.
+INSERT INTO mb_release_groups (mbid, title, primary_type, secondary_types, first_release_date, artist_credit)
+VALUES (sqlc.arg(mbid), sqlc.arg(title), sqlc.arg(primary_type), sqlc.arg(secondary_types)::text[],
+        sqlc.arg(first_release_date), sqlc.arg(artist_credit))
+ON CONFLICT (mbid) DO UPDATE SET
+    title              = EXCLUDED.title,
+    primary_type       = EXCLUDED.primary_type,
+    secondary_types    = EXCLUDED.secondary_types,
+    first_release_date = EXCLUDED.first_release_date,
+    artist_credit      = EXCLUDED.artist_credit,
+    updated_at         = now();
+
+-- name: GetMBReleaseGroup :one
+SELECT * FROM mb_release_groups WHERE mbid = sqlc.arg(mbid);
+
+-- name: DeleteMBArtistReleaseGroups :exec
+DELETE FROM mb_artist_release_groups WHERE artist_mbid = sqlc.arg(artist_mbid);
+
+-- name: AddMBArtistReleaseGroup :exec
+INSERT INTO mb_artist_release_groups (artist_mbid, release_group_mbid)
+VALUES (sqlc.arg(artist_mbid), sqlc.arg(release_group_mbid))
+ON CONFLICT DO NOTHING;
+
+-- name: ListMBArtistReleaseGroups :many
+-- An artist's discography, oldest first; undated groups last.
+SELECT g.* FROM mb_release_groups g
+JOIN mb_artist_release_groups ag ON ag.release_group_mbid = g.mbid
+WHERE ag.artist_mbid = sqlc.arg(artist_mbid)
+ORDER BY g.first_release_date = '', g.first_release_date, g.title, g.mbid;
+
+-- name: MarkMBReleaseGroupReleasesRefreshed :exec
+UPDATE mb_release_groups SET releases_refreshed_at = now() WHERE mbid = sqlc.arg(mbid);
+
+-- name: DeleteMBReleasesForGroup :exec
+-- Tracks go with their releases (ON DELETE CASCADE).
+DELETE FROM mb_releases WHERE release_group_mbid = sqlc.arg(release_group_mbid);
+
+-- name: InsertMBRelease :exec
+INSERT INTO mb_releases (mbid, release_group_mbid, title, status, release_date, country,
+                         disambiguation, formats, track_count)
+VALUES (sqlc.arg(mbid), sqlc.arg(release_group_mbid), sqlc.arg(title), sqlc.arg(status),
+        sqlc.arg(release_date), sqlc.arg(country), sqlc.arg(disambiguation), sqlc.arg(formats),
+        sqlc.arg(track_count))
+ON CONFLICT (mbid) DO UPDATE SET
+    release_group_mbid = EXCLUDED.release_group_mbid,
+    title              = EXCLUDED.title,
+    status             = EXCLUDED.status,
+    release_date       = EXCLUDED.release_date,
+    country            = EXCLUDED.country,
+    disambiguation     = EXCLUDED.disambiguation,
+    formats            = EXCLUDED.formats,
+    track_count        = EXCLUDED.track_count;
+
+-- name: InsertMBReleaseTrack :exec
+INSERT INTO mb_release_tracks (release_mbid, medium_position, position, medium_format, number,
+                               title, length_ms, recording_mbid)
+VALUES (sqlc.arg(release_mbid), sqlc.arg(medium_position), sqlc.arg(position),
+        sqlc.arg(medium_format), sqlc.arg(number), sqlc.arg(title), sqlc.arg(length_ms),
+        sqlc.arg(recording_mbid));
+
+-- name: ListMBReleasesForGroup :many
+-- Official editions first, then by date; undated last.
+SELECT * FROM mb_releases
+WHERE release_group_mbid = sqlc.arg(release_group_mbid)
+ORDER BY status <> 'Official', release_date = '', release_date, title, mbid;
+
+-- name: ListMBReleaseTracksForGroup :many
+SELECT t.* FROM mb_release_tracks t
+JOIN mb_releases r ON r.mbid = t.release_mbid
+WHERE r.release_group_mbid = sqlc.arg(release_group_mbid)
+ORDER BY t.release_mbid, t.medium_position, t.position;