curl --request POST \
  --url https://grantex-auth-dd4mtrt2gq-uc.a.run.app/v1/webauthn/register/options \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "principalId": "user_abc123"
}
'

{
  "challengeId": "<string>",
  "challenge": "<string>",
  "rp": {
    "name": "<string>",
    "id": "<string>"
  },
  "user": {
    "id": "<string>",
    "name": "<string>",
    "displayName": "<string>"
  },
  "pubKeyCredParams": [
    {
      "type": "<string>",
      "alg": 123
    }
  ],
  "authenticatorSelection": {
    "userVerification": "required"
  },
  "timeout": 123
}