feat: complete task 3 - fix sync.go cache-hit path to use centralized filter

internal/musicbrainz/sync.go

@@ -65,16 +65,7 @@ func SyncArtistDiscography(
 		if err != nil {
 			return nil, fmt.Errorf("sync artist discography: read artist filter options: %w", err)
 		}
-		filtered := make([]database.ExternalRelease, 0, len(cachedReleases))
-		for _, r := range cachedReleases {
-			if opts.IgnoreSingles && (r.Type == "Single" || hasSliceType(r.SecondaryTypes, "Single")) {
-				continue
-			}
-			if opts.IgnoreCompilations && (r.Type == "Compilation" || hasSliceType(r.SecondaryTypes, "Compilation")) {
-				continue
-			}
-			filtered = append(filtered, r)
-		}
+		filtered := ApplyTypeToggles(cachedReleases, opts)
 		return filtered, nil
 	}