Added limited local read/unread tracking

src/backend/models/items.py

@@ -82,6 +82,7 @@ class Room(ModelItem):
     last_event_date: datetime = ZeroDate
 
     mentions: int = 0
+    unreads: int = 0
 
     def __lt__(self, other: "Room") -> bool:
         """Sort by join state, then descending last event date, then name.