curl --request GET \
  --url https://flozy-backend-1042419926531.us-central1.run.app/api/v1/external/custom-fields \
  --header 'X-API-Key: <api-key>'

{
  "http_code": 200,
  "status": "success",
  "message": "Custom fields retrieved",
  "data": [
    {
      "id": 1,
      "name": "Company Size",
      "type": "select",
      "options": [
        "1-10",
        "11-50",
        "51-200",
        "200+"
      ]
    },
    {
      "id": 2,
      "name": "Annual Revenue",
      "type": "number",
      "options": null
    }
  ]
}