curl --request POST \
  --url https://backend.testeswaffle.org/referrals/subscribe \
  --header 'Content-Type: application/json' \
  --data '{
    "referrer_id": "usr_123456789",
    "referred_email": "indicado@exemplo.com",
    "referred_name": "Carlos Indicado",
    "newsletter": "thenews",
    "campaign": "janeiro_2024"
  }'

{
  "success": true,
  "data": {
    "referral_id": "ref_987654321",
    "status": "pending",
    "activation_email_sent": true,
    "referrer_count": 5
  }
}