SendMessageToDialogDto

{
    "content": "Привет! Как дела?",
    "list_id": "550e8400-e29b-41d4-a716-446655440001",
    "client_type": "web",
    "user_id": "anonymous",
    "recipient_type": "lead",
    "attachments": [
        {
            "storage_url": "https://attachments-ai.senler.ru/projects/xxx/dialogs/yyy/2025-12-27-uuid.jpg",
            "storage_path": "projects/xxx/dialogs/yyy/2025-12-27-uuid.jpg",
            "file_name": "screenshot.png",
            "mime_type": "image/png",
            "file_size": 1024000
        }
    ]
}