Fix outdated presence for lazy loaded members

src/backend/backend.py

@@ -6,7 +6,7 @@ import os
 import sys
 import traceback
 from pathlib import Path
-from typing import Any, DefaultDict, Dict, List, Optional
+from typing import TYPE_CHECKING, Any, DefaultDict, Dict, List, Optional
 
 from appdirs import AppDirs
 
@@ -23,6 +23,9 @@ from .models.model import Model
 from .models.model_store import ModelStore
 from .user_files import Accounts, History, Theme, UISettings, UIState
 
+if TYPE_CHECKING:
+    from .models.items import Presence
+
 # Logging configuration
 log.getLogger().setLevel(log.INFO)
 nio.logger_group.level = nio.log.logbook.ERROR
@@ -109,6 +112,8 @@ class Backend:
 
         self.media_cache: MediaCache = MediaCache(self, cache_dir)
 
+        self.presences: Dict[str, "Presence"] = {}
+
 
     def __repr__(self) -> str:
         return f"{type(self).__name__}(clients={self.clients!r})"