curl --request POST \
  --url https://backend.testeswaffle.org/referrals/ban \
  --header 'Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...' \
  --header 'Content-Type: application/json' \
  --data '{
    "email": "usuario.suspeito@exemplo.com",
    "reason": "Múltiplas tentativas de fraude detectadas"
  }'

{
  "success": true,
  "data": {
    "user_email": "usuario.suspeito@exemplo.com",
    "action": "banned",
    "banned_at": "2024-01-15T16:45:00Z",
    "reason": "Múltiplas tentativas de fraude detectadas"
  }
}