feat: Collection › Unmatched lists the library albums no MusicBrainz album matched, each matched by hand from a search or a link, or left off (M502 #5579)

Like Lidarr's Unmapped Files. A local band's album, which MusicBrainz will
never have, is left off: never matched again and not counted. A re-tagged
album is matched again on the next listing. The Collection's verdict now
says when library albums need matching.

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

internal/wanted/library.go

@@ -50,7 +50,10 @@ const libraryMatcher = 4
 //
 // Each album decided is recorded in library_album_matches, so an album taken
 // off the list stays off. Once done the listing runs again only for albums
-// an older matcher refused (libraryMatcher).
+// an older matcher refused (libraryMatcher), refused albums whose tracks
+// have changed since, and library tracks a re-tag filed under a new album
+// (#5579). A person matches the rest by hand, or leaves them off, in the
+// Collection's Unmatched section (MatchAlbumTo, LeaveAlbumOff).
 func (s *Service) listLibrary(ctx context.Context, res *PassResult) error {
 	q := dbq.New(s.pool)
 	state, err := q.GetLibraryListing(ctx)
@@ -58,9 +61,10 @@ func (s *Service) listLibrary(ctx context.Context, res *PassResult) error {
 		return fmt.Errorf("wanted: read the library listing: %w", err)
 	}
 	if state.LibraryListedAt.Valid {
-		stale, err := q.CountAlbumsToRematch(ctx, libraryMatcher)
+		stale, err := q.CountAlbumsToMatch(ctx, dbq.CountAlbumsToMatchParams{
+			Cutoff: state.LibraryListingStartedAt, Matcher: libraryMatcher})
 		if err != nil {
-			return fmt.Errorf("wanted: count refusals to retry: %w", err)
+			return fmt.Errorf("wanted: count albums to match again: %w", err)
 		}
 		if stale == 0 {
 			return nil