curl --request POST \
  --url https://agents.nineteen58.co.za/public-api/campaigns/{id}/add-leads \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '
{
  "type": "csv",
  "csvData": "<string>"
}
'

{
  "status": "<string>",
  "message": "<string>",
  "data": {
    "campaignId": "<string>",
    "totalContacts": 123,
    "successCount": 123,
    "errorCount": 123,
    "processedContacts": [
      {
        "identifier": "<string>",
        "contactId": "<string>",
        "action": "<string>"
      }
    ]
  }
}