curl --request POST \
  --url https://api.capitalcheckin.app/v1/collaborators/import-excel \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: multipart/form-data' \
  --form file='@example-file'

{
  "message": "<string>",
  "total_rows": 123,
  "valid_rows": 123,
  "invalid_rows": 123,
  "preview": [
    {
      "name": "<string>",
      "email": "jsmith@example.com",
      "position": "<string>",
      "department": "<string>",
      "phone": "<string>",
      "hire_date": "2023-12-25",
      "salary": 123,
      "manager_id": "<string>",
      "work_schedule": "<string>",
      "location": "<string>",
      "emergency_contact": {
        "name": "<string>",
        "phone": "<string>",
        "relationship": "<string>"
      }
    }
  ]
}