curl --request POST \
  --url https://openapi.enginy.ai/v1/add-contact-to-campaign \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '
{
  "campaignId": 123,
  "contactId": 123
}
'

{
  "status": "success",
  "message": "<string>",
  "data": {
    "conversationId": 123,
    "conversationStatus": "<string>",
    "campaignStatus": "<string>"
  }
}