curl --request GET \
  --url https://folksbase.onrender.com/api/imports/{id}/preview \
  --header 'Authorization: Bearer <token>'

{
  "importId": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "preview": {
    "headers": [
      "<string>"
    ],
    "rows": [
      [
        "<string>"
      ]
    ],
    "totalRows": 123
  },
  "suggestions": [
    {
      "header": "<string>",
      "field": "<string>",
      "confidence": "high"
    }
  ]
}