feat(performance): Implement callback cleanup mechanism

Add unregister_callback method and track callbacks for cleanup
to prevent memory leaks when actions are destroyed.

Changes:
- backend.py: Add unregister_callback() method
- actions/DiscordCore.py: Add callback tracking list
- actions/DiscordCore.py: Add register_backend_callback() helper
- actions/DiscordCore.py: Add cleanup_callbacks() method
- actions/DiscordCore.py: Add __del__() for automatic cleanup
- actions/Mute.py: Use register_backend_callback()
- actions/Deafen.py: Use register_backend_callback()
- actions/TogglePTT.py: Use register_backend_callback()
- actions/ChangeVoiceChannel.py: Use register_backend_callback()

Impact: Prevents memory leak in long-running sessions

Resolves issue #14 from RESEARCH.md Phase 3

Author: ImDevinC

actions/ChangeVoiceChannel.py

@@ -21,23 +21,20 @@ def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self.has_configuration = True
         self._current_channel: str = ""
-        self.icon_keys = [Icons.VOICE_CHANNEL_ACTIVE,
-                          Icons.VOICE_CHANNEL_INACTIVE]
+        self.icon_keys = [Icons.VOICE_CHANNEL_ACTIVE, Icons.VOICE_CHANNEL_INACTIVE]
         self.current_icon = self.get_icon(Icons.VOICE_CHANNEL_INACTIVE)
         self.icon_name = Icons.VOICE_CHANNEL_INACTIVE
 
     def on_ready(self):
         super().on_ready()
-        self.backend.register_callback(
-            VOICE_CHANNEL_SELECT, self._update_display)
+        self.register_backend_callback(VOICE_CHANNEL_SELECT, self._update_display)
 
     def _update_display(self, value: dict):
         if not self.backend:
             self.show_error()
             return
         self.hide_error()
-        self._current_channel = value.get(
-            "channel_id", None) if value else None
+        self._current_channel = value.get("channel_id", None) if value else None
         self.icon_name = (
             Icons.VOICE_CHANNEL_INACTIVE
             if self._current_channel is None

actions/Deafen.py

@@ -27,8 +27,7 @@ def __init__(self, *args, **kwargs):
 
     def on_ready(self):
         super().on_ready()
-        self.backend.register_callback(
-            VOICE_SETTINGS_UPDATE, self._update_display)
+        self.register_backend_callback(VOICE_SETTINGS_UPDATE, self._update_display)
 
     def create_event_assigners(self):
         self.event_manager.add_event_assigner(

actions/DiscordCore.py

@@ -23,6 +23,9 @@ def __init__(self, *args, **kwargs):
         self.color_name: str = ""
         self.backend: "Backend" = self.plugin_base.backend
 
+        # Track registered callbacks for cleanup
+        self._registered_callbacks: list[tuple[str, callable]] = []
+
         self.plugin_base.asset_manager.icons.add_listener(self._icon_changed)
         self.plugin_base.asset_manager.colors.add_listener(self._color_changed)
 
@@ -40,6 +43,25 @@ def create_generative_ui(self):
     def create_event_assigners(self):
         pass
 
+    def register_backend_callback(self, key: str, callback: callable):
+        """Register a callback and track it for cleanup."""
+        self.backend.register_callback(key, callback)
+        self._registered_callbacks.append((key, callback))
+
+    def cleanup_callbacks(self):
+        """Unregister all tracked callbacks to prevent memory leaks."""
+        for key, callback in self._registered_callbacks:
+            self.backend.unregister_callback(key, callback)
+        self._registered_callbacks.clear()
+
+    def __del__(self):
+        """Clean up callbacks when action is destroyed."""
+        try:
+            self.cleanup_callbacks()
+        except (AttributeError, RuntimeError):
+            # Object may be partially initialized or backend already destroyed
+            pass
+
     def display_icon(self):
         if not self.current_icon:
             return

actions/Mute.py

@@ -27,8 +27,7 @@ def __init__(self, *args, **kwargs):
 
     def on_ready(self):
         super().on_ready()
-        self.backend.register_callback(
-            VOICE_SETTINGS_UPDATE, self._update_display)
+        self.register_backend_callback(VOICE_SETTINGS_UPDATE, self._update_display)
 
     def create_event_assigners(self):
         self.event_manager.add_event_assigner(

actions/TogglePTT.py

@@ -30,8 +30,7 @@ def __init__(self, *args, **kwargs):
 
     def on_ready(self):
         super().on_ready()
-        self.backend.register_callback(
-            VOICE_SETTINGS_UPDATE, self._update_display)
+        self.register_backend_callback(VOICE_SETTINGS_UPDATE, self._update_display)
 
     def create_event_assigners(self):
         self.event_manager.add_event_assigner(

backend.py

@@ -134,6 +134,17 @@ def register_callback(self, key: str, callback: callable):
         if self._is_authed:
             self.discord_client.subscribe(key)
 
+    def unregister_callback(self, key: str, callback: callable):
+        """Remove a callback from the callback list."""
+        callbacks = self.callbacks.get(key, [])
+        if callback in callbacks:
+            callbacks.remove(callback)
+            if callbacks:
+                self.callbacks[key] = callbacks
+            else:
+                # Remove key entirely if no callbacks remain
+                del self.callbacks[key]
+
     def _ensure_connected(self) -> bool:
         """Ensure client is connected, trigger reconnection if needed."""
         if self.discord_client is None or not self.discord_client.is_connected():