Listar campos personalizados

GET /v1/custom-fields

curl "https://api.socialsell.ai/v1/custom-fields?entity=contact" \
  -H "Authorization: Bearer sk_live_..."

{
  "data": [
    {
      "id": "664n9o0p1q2r3s4t5u6v7w8x",
      "key": "cpf",
      "label": "CPF",
      "type": "text",
      "entity": "contact",
      "options": [],
      "default_value": null,
      "required": false,
      "is_active": true
    }
  ],
  "meta": { "total": 1, "has_more": false }
}