DialogLastMessageDto

{
    "content": "Привет! Как дела?",
    "role": "user",
    "timestamp": "2026-01-09T16:25:49.680Z",
    "event_type": "message",
    "attachments": [
        {
            "type": "photo",
            "count": 2
        },
        {
            "type": "document",
            "count": 1
        }
    ]
}