feat(backend): read time of my messages from the archive, exact dates and group readers asked from telegram on demand

backend/src/api/realtime.py

@@ -1,6 +1,7 @@
 import asyncio
 import json
 import logging
+from datetime import UTC, datetime
 from typing import Any
 
 import asyncpg
@@ -114,6 +115,7 @@ class EventHub:
                 "type": "receipt",
                 "chat_id": event["chat_id"],
                 "read_up_to": event["message_id"],
+                "read_at": datetime.now(UTC).isoformat(),
             }
         return None