Phase-2 Slice 8. Adds "Add to Mixtape/Collection" everywhere "Add to playlist"
lives, so collections can be populated:
- ui/myqbz/AddToMixtapeModal.slint: the picker (search + collection list with
kind icon/name/count + "Already added" via item_exists + kind tag) and the
create-new-inline panel (name + kind), per spec 21. Mounted once at root.
- src/myqbz_add.rs: list_collections (kind-restricted: track/playlist->mixtapes,
album->mixtapes+collections, never artist_collection; recency-sorted); add via
add_item_with(allow_duplicate=false) counting added/skipped-duplicates + toast;
create_and_add reuses create_collection. All via with_db -> with_connection.
- Entry points wired: per-track (universal via TrackContextMenu/TrackRow -> search,
favorites, album rows, local tracks, now-playing), Qobuz album, local/plex album,
playlist (PM), bulk local tracks. Replaced the PlaylistManager add-to-mixtape no-op.
Qobuz bulk omitted by design (spec 50 negative-space).
Note: adversarial reviewers were blocked by a session limit; verified manually
(cargo green, confined to qbz-slint, backend untouched, ADR-005/006, coverage per
spec 50).
cc