Selection grows file-manager gestures — shift-click ranges (additive,
anchored on the last plain toggle) and press-and-hold on touch — and a
floating toolbar appears with the selected count and the bulk verbs:
change type, link condition, delete, clear. All verbs drive the bulk
endpoint in <=100-id chunks with merged per-id results; partial failures
surface as one counted toast, and a bulk delete gets one aggregate undo
that bulk-restores the succeeded rows (both sides no-op-safe by
contract). Escape clears the selection unless a dialog owns the key.
Refs: document-vault plan W3-T2