curl --request POST \
  --url https://api.kataven.ai/v1/api/v1/campaigns/{id}/start \
  --header 'Authorization: <api-key>'

{
  "agent_id": "<string>",
  "completed_at": "<string>",
  "created_at": "<string>",
  "created_by": "<string>",
  "id": "<string>",
  "max_concurrent_calls": 123,
  "name": "<string>",
  "phone_number_id": "<string>",
  "retries_per_contact": 123,
  "retry_delay_seconds": 123,
  "scheduled_at": "<string>",
  "started_at": "<string>",
  "status": "<string>"
}