perf: in-place media card update for live lyrics

app/src/main/assets/h5/js/pages/home.js

@@ -126,9 +126,30 @@ window.HearthEvents.mediaSessionChanged = function (infos) {
   }
   const grid = document.getElementById('tri-col');
   if (!grid) return;
+  // 若媒体卡已存在且还有媒体，增量更新（歌词实时变化时避免重建整个首页导致卡顿）
+  // If the media card exists and media is still active, update in place (avoid
+  // rebuilding the whole home on every live-lyrics change, which causes jank)
+  const card = grid.querySelector('.media-card');
+  if (card && currentMediaList && currentMediaList.length > 0) {
+    updateMediaCardInPlace(card, currentMediaList[currentMediaIndex]);
+    return;
+  }
   window.updateHomeCards();
 };
 
+// 增量更新媒体卡内容（标题/艺术家/封面/播放图标），不重建整个首页
+// Update the media card in place (title/artist/cover/play icon) without rebuilding
+function updateMediaCardInPlace(card, info) {
+  const tt = card.querySelector('.tt');
+  if (tt) tt.textContent = info.title;
+  const ar = card.querySelector('.ar');
+  if (ar) ar.textContent = info.artist;
+  const cover = card.querySelector('.cover');
+  if (cover && info.cover) cover.src = info.cover;
+  const playBtn = card.querySelector('[data-act="play"]');
+  if (playBtn) playBtn.innerHTML = info.playing ? ICON_PAUSE : ICON_PLAY;
+}
+
 // 媒体卡：封面 + 标题/艺术家 + 进度条 + 控制按钮 + 多会话滑动切换
 // Media card: cover + title/artist + progress + controls + multi-session swipe
 function renderMediaCard(info) {