curl --request GET \
  --url https://app.dynamicauth.com/api/v0/sdk/{environmentId}/users/passkeys/register \
  --header 'Authorization: Bearer <token>'

{
  "attestation": "direct",
  "authenticatorSelection": {
    "authenticatorAttachment": "cross-platform",
    "requireResidentKey": true,
    "residentKey": "discouraged",
    "userVerification": "discouraged"
  },
  "challenge": "<string>",
  "excludeCredentials": [
    {
      "id": "<string>",
      "type": "public-key",
      "transports": [
        "usb"
      ]
    }
  ],
  "pubKeyCredParams": [
    {
      "alg": 123,
      "type": "public-key"
    }
  ],
  "rp": {
    "id": "<string>",
    "name": "<string>"
  },
  "timeout": 123,
  "user": {
    "displayName": "<string>",
    "id": "<string>",
    "name": "<string>"
  },
  "extensions": {
    "appid": "<string>",
    "appidExclude": "<string>",
    "credProps": true,
    "uvm": true
  },
  "hints": [
    "<string>"
  ]
}