Extend the favorites tracks bulk bar beyond Remove: Play next and Add to
queue build the queue from the already-loaded Track objects (new
playback::enqueue_tracks, no re-fetch; play-next inserts in order), and
Add to playlist opens the picker for the whole selection. The picker
gains track-ids for bulk add (open_multi); on_pick adds every id via the
existing add_tracks_to_playlist. Make-offline stays out (no Slint
offline-cache path yet).
cc
vicrodh
07c71adb65