{"alice": {"session_id": "sess_alice", "origin": {"platform": "telegram", "chat_id": "-1001", "user_id": "alice"}, "updated_at": "2026-01-01T00:00:00"}, "bob": {"session_id": "sess_bob", "origin": {"platform": "telegram", "chat_id": "-1001", "user_id": "bob"}, "updated_at": "2026-02-01T00:00:00"}}