List Webhooks

{
  "success": true,
  "data": {
    "endpoints": [
      {
        "id": "550e8400-e29b-41d4-a716-446655440000",
        "url": "https://yourapp.com/webhooks",
        "events": ["email.delivered", "email.bounced"],
        "active": true,
        "created_at": "2026-03-07T12:00:00Z"
      }
    ]
  }
}