perf(消息列表): 使用虚拟列表优化聊天会话列表渲染性能

将普通列表替换为虚拟列表(n-virtual-list)，减少DOM节点数量以提升长列表的渲染性能

src/views/message/inner/IndexSider.vue

@@ -1146,8 +1146,10 @@ const handleEnterSearchResultChat = () => {
     <main id="talk-session-list" class="el-main me-scrollbar me-scrollbar-thumb">
       <template v-if="loadStatus == 2"><Skeleton /></template>
       <template v-else>
+         <n-virtual-list  :item-size="64" :items="items">
+    <template #default="{ item }">
       <TalkItem
-          v-for="item in items"
+  
           :key="item.index_name + item.unread_num"
           :data="item"
           :avatar="item.avatar"
@@ -1158,6 +1160,8 @@ const handleEnterSearchResultChat = () => {
           @contextmenu.prevent="onContextMenuTalk($event, item)"
         />
     </template>
+  </n-virtual-list>
+      </template>
     </main>
   </section>