Phase-2 Slice 10.
- ui/myqbz/MyQbzMixModal.slint + src/myqbz_mix.rs: the DJ-mix "random queue"
modal. Open resolves the collection in-order + shuffle::unique_track_count
(deterministic) for the slider max (buildSizeOptions). Shuffle re-resolves,
runs dedup_by_similarity + hybrid_sample with a thread RNG kept in a SYNC scope
(dropped before the next .await -- !Send confinement), then replace-plays +
stamps queue-source + touch_play; toasts "Playing N of M" when the per-album cap
shrinks the pool. Wired on_dj_mix.
- Detail bulk bar (MultiSelectBar, bottom-docked): add-selected -> AddToMixtapeModal
with the selected payloads; remove-selected -> repo::remove_item (highest position
first so compaction does not invalidate pending positions) -> reload + clear
selection + toast.
Deferred to polish: the bulk bar's queue / add-to-playlist / clear-X groups (§13.1).
Backend crates untouched. cargo check -p qbz-slint green.
cc