Breaking: Remove owner_access_key query parameter from REST v1 session endpoints. Delegation is now performed via owner_id (user UUID) and only on the session creation endpoints (/session/_/create-from-template, /session/_/create, /session/_/create-cluster). Read/control endpoints always act as the authenticated caller. Clients that previously passed owner_access_key=<AK> must migrate to owner_id=<user-uuid>.