Description

Update metadata retrieval to support signed metadata (application/jwt) alongside unsigned (application/json), including sending an Accept header and validating JWS headers (alg, typ: openidvci-issuer-metadata+jwt) and JWT claims (iss, sub, iat, exp).

See: https://openid.net/specs/openid-4-verifiable-credential-issuance-1_0-16.html#name-signed-metadata