frontend fixes

album artist gets populated with artist as fallback (frontend also uses
this as display name fallback for albums). added scroll position
persistence when switching main views. also added frontend cache for
faster switching.

backend/library/library.go

@@ -335,6 +335,8 @@ func (l *Library) Scan() error {
 		"library", l.conf.DirectoryPath,
 	)
 
+	runtime.EventsEmit(l.ctx, events.LibraryScanComplete)
+
 	return scanErr
 }
 
@@ -510,18 +512,27 @@ func (l *Library) processMetadata(result importResult) (int64, error) {
 		})
 	}
 
-	// 3. Get or create artist credit for album artist (if different)
+	// 3. Get or create artist credit for album artist.
+	// Always assign an album artist credit so the cover grid displays an
+	// artist name.  When the AlbumArtist tag is absent or identical to the
+	// track Artist, reuse the track artist credit instead of leaving it NULL.
 	var albumArtistCreditID sql.NullInt64
 
 	if tags.AlbumArtist != "" && tags.AlbumArtist != tags.Artist {
-		albumArtistCredit, err := l.db.Queries.UpsertArtistCredit(l.ctx, tags.AlbumArtist)
+		albumArtistCredit, err := l.db.Queries.UpsertArtistCredit(
+			l.ctx, tags.AlbumArtist,
+		)
 		if err != nil {
 			l.logger.Warn("could not upsert album artist credit", "err", err)
 		} else {
-			albumArtistCreditID = sql.NullInt64{Int64: albumArtistCredit.ID, Valid: true}
+			albumArtistCreditID = sql.NullInt64{
+				Int64: albumArtistCredit.ID, Valid: true,
+			}
 
-			// Also create the artist record and link
-			albumArtist, err := l.db.Queries.UpsertArtist(l.ctx, tags.AlbumArtist)
+			// Also create the artist record and link.
+			albumArtist, err := l.db.Queries.UpsertArtist(
+				l.ctx, tags.AlbumArtist,
+			)
 			if err != nil {
 				l.logger.Warn("could not upsert album artist", "err", err)
 			} else {
@@ -534,6 +545,12 @@ func (l *Library) processMetadata(result importResult) (int64, error) {
 				)
 			}
 		}
+	} else {
+		// AlbumArtist is empty or matches the track artist — reuse the
+		// track artist credit so the release group always has an artist.
+		albumArtistCreditID = sql.NullInt64{
+			Int64: artistCredit.ID, Valid: true,
+		}
 	}
 
 	// 4. Get or create release group (album)