fix(lidarr): include artistName + metadataProfileId on add-artist/add-album

The 'lidarr_rejected' the operator was hitting on Approve was Lidarr 4xx-ing
the POST with two field-validation errors:

  'Metadata Profile Id' must be greater than '0'.
  'Artist Name' must not be empty.

Our payload was missing both. Lidarr's metadata profile is a separate
concept from quality profile (it controls which release types are
tracked: albums, singles, EPs, etc.) and is required by /api/v1/artist
and /api/v1/album. The 'already exists' line in the toast copy was an
incorrect guess at the cause; the real issue was an invalid payload.

Changes:

- internal/lidarr/types.go: AddArtistParams + AddAlbumParams gain
  ArtistName and MetadataProfileID. New MetadataProfile struct mirroring
  QualityProfile.
- internal/lidarr/client.go: AddArtist + AddAlbum payloads include both
  new fields. New ListMetadataProfiles fetches GET /api/v1/metadataprofile.
- internal/lidarrrequests/service.go: Approve fetches the metadata
  profile list and uses the first as a default (Lidarr installs ship
  'Standard' at id=1 OOB, so this works for vanilla setups). Picker
  on /admin/integrations is a follow-up. ArtistName flows from the
  request row.
- web/src/routes/admin/requests/+page.svelte: drop the
  speculative 'usually means already in library' copy on lidarr_rejected;
  point operators at server logs for the field-level reason instead.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

internal/lidarrrequests/service.go

@@ -178,10 +178,31 @@ func (s *Service) Approve(ctx context.Context, requestID pgtype.UUID, adminID pg
 		return dbq.LidarrRequest{}, ErrDefaultsIncomplete
 	}
 
+	// Lidarr requires a metadata profile id on POST /api/v1/artist (and
+	// on /api/v1/album when it has to create the parent artist). We
+	// don't store this in lidarr_config yet — fetch the available
+	// profiles per-Approve and pick the first as a sensible default.
+	// Lidarr installs ship "Standard" at id=1 OOB, so this works for
+	// vanilla setups; operators with custom profiles get whichever was
+	// saved first. A picker on /admin/integrations is a follow-up.
+	mdProfiles, err := client.ListMetadataProfiles(ctx)
+	if err != nil {
+		return dbq.LidarrRequest{}, fmt.Errorf("approve: list metadata profiles: %w", err)
+	}
+	if len(mdProfiles) == 0 {
+		return dbq.LidarrRequest{}, fmt.Errorf("approve: no metadata profiles configured in lidarr")
+	}
+	mdProfileID := mdProfiles[0].ID
+
 	switch row.Kind {
 	case dbq.LidarrRequestKindArtist:
 		err = client.AddArtist(ctx, lidarr.AddArtistParams{
-			ForeignArtistID: row.LidarrArtistMbid, QualityProfileID: qp, RootFolderPath: rf, MonitorAll: true,
+			ForeignArtistID:   row.LidarrArtistMbid,
+			ArtistName:        row.ArtistName,
+			QualityProfileID:  qp,
+			MetadataProfileID: mdProfileID,
+			RootFolderPath:    rf,
+			MonitorAll:        true,
 		})
 	case dbq.LidarrRequestKindAlbum, dbq.LidarrRequestKindTrack:
 		// Track-kind requests promote to album-add; the spec is explicit.
@@ -190,8 +211,12 @@ func (s *Service) Approve(ctx context.Context, requestID pgtype.UUID, adminID pg
 			albumMBID = *row.LidarrAlbumMbid
 		}
 		err = client.AddAlbum(ctx, lidarr.AddAlbumParams{
-			ForeignAlbumID: albumMBID, ForeignArtistID: row.LidarrArtistMbid,
-			QualityProfileID: qp, RootFolderPath: rf,
+			ForeignAlbumID:    albumMBID,
+			ForeignArtistID:   row.LidarrArtistMbid,
+			ArtistName:        row.ArtistName,
+			QualityProfileID:  qp,
+			MetadataProfileID: mdProfileID,
+			RootFolderPath:    rf,
 		})
 	}
 	if err != nil {