Push rules sound: be a string, not just on/off

src/backend/models/items.py

@@ -107,7 +107,7 @@ class PushRule(ModelItem):
     notify:       bool            = False
     highlight:    bool            = False
     bubble:       bool            = False
-    sound:        bool            = False
+    sound:        str             = ""  # usually "default" when set
     urgency_hint: bool            = False
 
     def __lt__(self, other: "PushRule") -> bool:

src/backend/models/model.py

@@ -108,7 +108,11 @@ class Model(MutableMapping):
                 del self._sorted_data[index_then]
 
             self._sorted_data.add(new)
-            index_now = self._sorted_data.index(new)
+            try:
+                index_now = self._sorted_data.index(new)
+            except ValueError:
+                import remote_pdb; remote_pdb.RemotePdb("127.0.0.1", 4444).set_trace()
+                pass
 
             # Insert into dict data