Enhance volume persistence with logging

Add logging for volume persistence and conditionally skip saving if unchanged.

linux_voice_assistant/models.py

@@ -110,14 +110,18 @@ class ServerState:
     def persist_volume(self, volume: float) -> None:
         """Persist the normalized media volume (0.0 - 1.0)."""
         clamped_volume = max(0.0, min(1.0, volume))
+        _LOGGER.debug(f"persist_volume called: new={clamped_volume}, current={self.volume}, prefs={self.preferences.volume}")
 
         if (
             abs(self.volume - clamped_volume) < 0.0001
             and self.preferences.volume is not None
             and abs(self.preferences.volume - clamped_volume) < 0.0001
         ):
+            _LOGGER.debug("Skipping save - volume unchanged")
             return
 
         self.volume = clamped_volume
         self.preferences.volume = clamped_volume
+        _LOGGER.info(f"Saving volume {clamped_volume} to {self.preferences_path}")
         self.save_preferences()
+        _LOGGER.info(f"Volume saved successfully")