OptionalalbumOpaque identity used when display names cannot identify the album.
OptionalartistThe row's data-artist: the parent artist of an album row in the
artist view, or the album artist of a group in the album view, which
with key names the album for library.getAlbumTracks when albumId
is absent. Absent on other rows.
Full selection set (anchor + range or ctrl-toggled rows).
OptionaltracksExact members of an artist's album row; pass them to addToPlaylist.
'group' | 'album' | 'track' — mirrors the row's data-type.
Active view at the time of the click ('artist' | 'album' | 'genre').
<fb-library-tree>row clicked — selection state updated.