List redacted sandbox matter documents

Returns redacted sandbox document manifest metadata when the authenticated automation client has transactions.documents.read. External URL: /v1/conveyancing/matters/{id}/documents. Current Next.js implementation path: /api/platform/v1/conveyancing/matters/[id]/documents. This read-only route never returns raw document contents, hidden storage paths, permanent links, private legal notes, privileged communications, or production signed URLs. Conveyancing pilot posture remains marketplace orchestration only, legal advice and client-money or trust-account handling remain deferred, and partner-status publication remains private-first.