Fix peripheral volume_muted state (#403)

Enable updating the `volume_muted` status when muting/unmuting the media player volume, and improve its tracking.

linux_voice_assistant/models.py

@@ -217,6 +217,7 @@ class ServerState:
             _LOGGER.debug("Skipping save - volume unchanged")
             return
 
+        previous_muted = self.volume == 0.0
         self.volume = clamped_volume
         self.preferences.volume = clamped_volume
         _LOGGER.info("Saving volume %s to %s", clamped_volume, self.preferences_path)
@@ -230,6 +231,10 @@ class ServerState:
 
             api.emit_event_sync(LVAEvent.VOLUME_CHANGED, {"volume": round(clamped_volume, 3)})
 
+            new_muted = clamped_volume == 0.0
+            if previous_muted != new_muted:
+                api.emit_event_sync(LVAEvent.VOLUME_MUTED, {"muted": new_muted})
+
     def persist_mic_gain(self, gain: float) -> None:
         """Persist the microphone auto gain value."""
         gain_int = int(gain)