DELETE /pages/:id?mode=promote|subtree — promote (the default) moves
the page's live children up to its parent; subtree trashes every live
descendant with one timestamp and requires write permission on all of
them (no partial deletes; trash access is write capability, ADR 0013).
Trashed pages keep their parentId. Restore re-attaches to the nearest
live ancestor (else root), which makes restore order-independent:
restoring a parent afterwards never re-claims an already-restored
child. Purge promotes any remaining children to the purged page's
parent; the FK's SetNull stays as backstop only.
tree-trash.e2e.db.test.ts covers promote, subtree + one-timestamp,
the 403 descendant gate (label-DENY editor), order-independent
restore, and child promotion on purge.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
