An authorization code (stored hashed). dpop_jkt is the thumbprint of
the DPoP key the code is bound to (RFC 9449 §10), or nil: the token
request that redeems a bound code must carry a proof made with that
key. acr and auth_time are how and when the person signed in
when they approved it (Sake.Auth.Subject.authentication/1), or
nil, which its tokens carry (RFC 9470). nonce is the authorization
request's OpenID Connect nonce, or nil, which the ID token issued
for the code carries.