test: the album-copy fold test makes each album once, as UpsertAlbum folds only by MBID (#5401)

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

internal/library/song_link_test.go

@@ -234,11 +234,17 @@ func TestResolveDuplicates_FoldsAnAlbumsExtraCopyInACrossReleaseGroup_Integratio
 	if err != nil {
 		t.Fatal(err)
 	}
+	// UpsertAlbum folds only by MBID, so each album is made once.
+	albums := map[string]dbq.Album{}
 	track := func(album, name, format string) dbq.Track {
 		t.Helper()
-		a, err := q.UpsertAlbum(ctx, dbq.UpsertAlbumParams{Title: album, SortTitle: album, ArtistID: artist.ID})
-		if err != nil {
-			t.Fatal(err)
+		a, ok := albums[album]
+		if !ok {
+			var err error
+			if a, err = q.UpsertAlbum(ctx, dbq.UpsertAlbumParams{Title: album, SortTitle: album, ArtistID: artist.ID}); err != nil {
+				t.Fatal(err)
+			}
+			albums[album] = a
 		}
 		path := filepath.Join(dir, album, name)
 		if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {