Defines a new MicMuteSwitchEntity class that creates the switch entity in Home Assistant.
When the switch is toggled, it publishes a set_mic_mute event to the internal event bus with the new state (True for muted, False for unmuted).
Updates the MediaPlayerEntity to handle the saving and loading logic.
The entity's internal volume state is now initialized from the saved preferences.volume_level.
When a volume change command is received from Home Assistant, the handle_message method now updates the Preferences object and calls save_preferences() to persist the new volume level to disk.