Verify a Refusal Record’s signature.Maps to POST /refusal/verify — takes the record itself, not a
lookup by id. No caller authentication is required by this
route: it is the capability that makes a refusal independently
third-party verifiable (RFC-0021).
Retrieve a Refusal Record by Business Transaction ID.Maps to GET /refusal/:businessTransactionId. Unlike verify()
above, this route is behind caller-auth and ownership scoping,
identically to TrustRecordApi.get().