JwkOctSerializer
Serializer for Jwk.Oct values to and from their JSON Web Key representation per RFC 7517.
Encodes the symmetric key material (k) as a Base64URL string, along with optional metadata fields (use, key_ops, alg, kid). Throws co.touchlab.kjwt.exception.MalformedJwkException during deserialization if the required k field is missing.