Use the primary artist for upload destination folders

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

services/api/internal/uploads/placement.go

@@ -123,7 +123,7 @@ func (s *PlacementPlanner) plan(ctx context.Context, f File, m Meta, chosen *uui
 		pl    placement
 		discs int // дисков в альбоме: в каталоге, в пачке, у самого файла
 	)
-	if artist, album, maxDisc, err := s.store.MatchCatalog(ctx, meta.Key(m.AlbumArtist), meta.Key(m.Album)); err == nil {
+	if artist, album, maxDisc, err := s.store.MatchCatalog(ctx, meta.Key(m.PrimaryArtist()), meta.Key(m.Album)); err == nil {
 		pl.ArtistID, pl.AlbumID, discs = artist, album, maxDisc
 	}
 	src, reason := s.pickSource(ctx, chosen)