curl --request POST \
  --url 'http://{{baseurl}}/api/v1/client/{environmentId}/user' \
  --header 'Content-Type: application/json' \
  --data '
{
  "attributes": {
    "plan": "free"
  },
  "userId": "hello-user"
}
'

{
  "data": {
    "state": {
      "data": {
        "displays": [
          {
            "createdAt": "2025-02-03T11:23:13.050Z",
            "surveyId": "cm6orqtdd000a19wjhnbces5s"
          }
        ],
        "lastDisplayAt": "2025-02-03T11:23:13.050Z",
        "responses": [
          "cm6orqtdd000a19wjhnbces5s"
        ],
        "segments": [
          "cm6onrezn000hw2ahcokiz41v"
        ],
        "userId": "hello-user"
      },
      "expiresAt": "2025-02-03T11:23:13.050Z"
    }
  }
}