Write-lock when refiltering

TODO.md

@@ -11,6 +11,7 @@
 - fix left rooms opacity
 - fix escape keybinds (filter rooms, message selection)
 - fix nio 429
+- fix python getting stuck when loading large room
 
 - account delegates refactor
 - lag when switching accounts

src/backend/models/filters.py

@@ -55,6 +55,7 @@ class ModelFilter(ModelProxy):
 
 
     def refilter(self) -> None:
+        with self._write_lock:
             take_out   = []
             bring_back = []