refactor(music-player): 优化 currentMusic 变化监听逻辑- 修改 watch 监听方式，使用箭头函数监听 currentMusic.value?.id 的变化

-增加对当前音乐对象的存在性检查
- 保留原有的立即执行行为

music-qianduan/src/components/MusicPlayer.vue

@@ -546,8 +546,11 @@ const scrollToActiveLyric = async () => {
 }
 
 // 监听当前播放歌曲的变化
-watch(currentMusic, (newMusic) => {
-  if (newMusic && newMusic.id) {
+watch(() => currentMusic.value?.id, (newId) => {
+  if (newId) {
+    const newMusic = playerStore.getCurrentMusic;
+    if (!newMusic) return;
+
     // 处理 URL
     playerStore.updateMusicUrl(newMusic.id, processMusicUrl(newMusic.url))
     playerStore.updateMusicCover(newMusic.id, processMusicUrl(newMusic.cover))
@@ -571,7 +574,7 @@ watch(currentMusic, (newMusic) => {
     lyricLines.value = {}
     if (isExpanded.value) expandedActiveTab.value = 'lyric'
   }
-}, { deep: true })
+}, { immediate: true })
 </script>
 
 <style scoped>