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>

android/app/src/main/java/com/fabledsword/minstrel/api/endpoints/DiscoverApi.kt

@@ -13,10 +13,11 @@ import retrofit2.http.Path
 import retrofit2.http.Query
 
 /**
- * Retrofit interface for Discover / Lidarr search / request creation.
+ * Retrofit interface for Discover / catalogue search / request creation.
  *
- * `/api/lidarr/search` has a 60s LRU on the server so quick re-types
- * of the same query are cheap.
+ * `/api/catalogue/search` asks MusicBrainz, which allows one request a
+ * second, so the Discover screen searches when the query is submitted,
+ * not on every keystroke.
  *
  * Cancel + my-requests-list endpoints live on RequestsApi (Phase 10
  * Commit B), not here.
@@ -25,7 +26,7 @@ interface DiscoverApi {
     @GET("api/discover/suggestions")
     suspend fun listSuggestions(): List<ArtistSuggestionWire>
 
-    @GET("api/lidarr/search")
+    @GET("api/catalogue/search")
     suspend fun search(
         @Query("q") query: String,
         @Query("kind") kind: String,

android/app/src/main/java/com/fabledsword/minstrel/discover/ui/DiscoverTiles.kt

@@ -25,7 +25,6 @@ import androidx.compose.ui.draw.clip
 import androidx.compose.ui.graphics.vector.ImageVector
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
-import coil3.compose.AsyncImage
 import com.composables.icons.lucide.Clock
 import com.composables.icons.lucide.Disc3
 import com.composables.icons.lucide.Lucide
@@ -33,6 +32,7 @@ import com.composables.icons.lucide.User
 import com.fabledsword.minstrel.models.ArtistSuggestionRef
 import com.fabledsword.minstrel.models.LidarrSearchResultRef
 import com.fabledsword.minstrel.models.SuggestionSnoozeRef
+import com.fabledsword.minstrel.shared.widgets.ServerImage
 
 @Composable
 internal fun SuggestionTile(
@@ -173,18 +173,19 @@ private fun Avatar(imageUrl: String, fallback: ImageVector, circular: Boolean) {
             .background(MaterialTheme.colorScheme.surfaceVariant),
         contentAlignment = Alignment.Center,
     ) {
-        if (imageUrl.isEmpty()) {
+        // The server hands back its own art endpoint (relative, M502 #5519),
+        // which answers 404 when no source has an image: ServerImage resolves
+        // the path and shows the icon while loading and on a miss.
+        ServerImage(
+            url = imageUrl,
+            contentDescription = null,
+            modifier = Modifier.fillMaxSize(),
+        ) {
             Icon(
                 imageVector = fallback,
                 contentDescription = null,
                 tint = MaterialTheme.colorScheme.onSurfaceVariant,
             )
-        } else {
-            AsyncImage(
-                model = imageUrl,
-                contentDescription = null,
-                modifier = Modifier.fillMaxSize(),
-            )
         }
     }
 }

android/app/src/main/java/com/fabledsword/minstrel/models/wire/DiscoverWire.kt

@@ -4,9 +4,10 @@ import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 
 /**
- * One row of `GET /api/lidarr/search`. Mirrors
- * `web/src/lib/api/types.ts LidarrSearchResult` /
- * the Flutter client's `LidarrSearchResult`.
+ * One row of `GET /api/catalogue/search` (the MusicBrainz search that replaced
+ * Lidarr's, M502 #5519). Mirrors `web/src/lib/api/types.ts
+ * CatalogueSearchResult`. `imageUrl` is the server's own art endpoint,
+ * relative, so it goes through ServerImage.
  *
  * `inLibrary` and `requested` let the UI greyout rows the user can't
  * act on (already imported / already awaiting review). All defaults