media_player: handle STOP command correctly (fixes #128)

Home Assistant sends MEDIA_PLAYER_COMMAND_STOP when the queue is cleared.
The MediaPlayer entity did not handle this command, causing playback to
continue without media metadata and leaving the UI in an inconsistent state.

This change adds explicit handling for the STOP command:
- stop playback via the music player
- reset the media player state to IDLE

This aligns the behavior with the original player and Home Assistant’s
expected media player semantics.

linux_voice_assistant/entity.py

@@ -1,6 +1,7 @@
 from abc import abstractmethod
 from collections.abc import Iterable
 from typing import Callable, List, Optional, Union
+import logging
 
 # pylint: disable=no-name-in-module
 from aioesphomeapi.api_pb2 import (  # type: ignore[attr-defined]
@@ -68,6 +69,7 @@ class MediaPlayerEntity(ESPHomeEntity):
         self.previous_volume = 1.0
         self.music_player = music_player
         self.announce_player = announce_player
+        self._log = logging.getLogger(f"{self.__class__.__name__}[{self.key}]")
 
     def play(
         self,
@@ -111,19 +113,37 @@ class MediaPlayerEntity(ESPHomeEntity):
         yield self._update_state(MediaPlayerState.PLAYING)
 
     def handle_message(self, msg: message.Message) -> Iterable[message.Message]:
+        self._log.debug("handle_message called with msg: %s", msg)
+
         if isinstance(msg, MediaPlayerCommandRequest) and (msg.key == self.key):
+            self._log.debug("MediaPlayerCommandRequest matched for this key")
+
             if msg.has_media_url:
+                self._log.debug("Message has media URL: %s", msg.media_url)
                 announcement = msg.has_announcement and msg.announcement
                 yield from self.play(msg.media_url, announcement=announcement)
+
             elif msg.has_command:
+                self._log.debug("Message has command: %s", msg.command)
                 command = MediaPlayerCommand(msg.command)
+
                 if msg.command == MediaPlayerCommand.PAUSE:
+                    self._log.debug("Executing PAUSE")
                     self.music_player.pause()
                     yield self._update_state(MediaPlayerState.PAUSED)
+
                 elif msg.command == MediaPlayerCommand.PLAY:
+                    self._log.debug("Executing PLAY / RESUME")
                     self.music_player.resume()
                     yield self._update_state(MediaPlayerState.PLAYING)
+
+                elif command == MediaPlayerCommand.STOP:
+                    self._log.debug("Executing STOP")
+                    self.music_player.stop()
+                    yield self._update_state(MediaPlayerState.IDLE)
+
                 elif command == MediaPlayerCommand.MUTE:
+                    self._log.debug("Executing MUTE")
                     if not self.muted:
                         self.previous_volume = self.volume
                         self.volume = 0
@@ -131,20 +151,26 @@ class MediaPlayerEntity(ESPHomeEntity):
                         self.announce_player.set_volume(0)
                         self.muted = True
                     yield self._update_state(self.state)
+
                 elif command == MediaPlayerCommand.UNMUTE:
+                    self._log.debug("Executing UNMUTE")
                     if self.muted:
                         self.volume = self.previous_volume
                         self.music_player.set_volume(int(self.volume * 100))
                         self.announce_player.set_volume(int(self.volume * 100))
                         self.muted = False
                     yield self._update_state(self.state)
+
             elif msg.has_volume:
+                self._log.debug("Message has volume: %.2f", msg.volume)
                 volume = int(msg.volume * 100)
                 self.music_player.set_volume(volume)
                 self.announce_player.set_volume(volume)
                 self.volume = msg.volume
                 yield self._update_state(self.state)
+
         elif isinstance(msg, ListEntitiesRequest):
+            self._log.debug("ListEntitiesRequest received")
             yield ListEntitiesMediaPlayerResponse(
                 object_id=self.object_id,
                 key=self.key,
@@ -153,7 +179,10 @@ class MediaPlayerEntity(ESPHomeEntity):
                 feature_flags=SUPPORTED_MEDIA_PLAYER_FEATURES,
             )
         elif isinstance(msg, SubscribeHomeAssistantStatesRequest):
+            self._log.debug("SubscribeHomeAssistantStatesRequest received")
             yield self._get_state_message()
+        else:
+            self._log.warning("Unknown message type received: %s", type(msg))
 
     def _update_state(self, new_state: MediaPlayerState) -> MediaPlayerStateResponse:
         self.state = new_state