Provisional credentials returned by the DG onramp complete endpoint.
Store client_id and client_secret securely — the secret is shown
exactly once and cannot be recovered after this point.
mcp_url and rpc_url are provisioned as part of the identity
registration step and may be absent from the initial onramp response.
Use DatagroutConduit.Client.bootstrap_onramp/1 for the all-in-one flow
that handles this transparently.