GET /api/v1/document-folders → full tree (documents.view).
POST /api/v1/document-folders → create (documents.manage_folders).
PATCH /api/v1/document-folders/[id] → rename OR move (union schema —
refuses both in one body so audit logs stay one-op-per-call).
DELETE /api/v1/document-folders/[id] → soft-rescue delete; returns 204.
PATCH passes ctx.userId through to the service-level audit-log
emitters (renameFolder + moveFolder gained userId in Task 4 fixes).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
