fix: 修复历史记录列表重复显示问题

- 添加去重逻辑，防止相同ID的历史记录被重复添加
- 防止滚动事件监听器重复注册
- 添加请求ID防止并发加载
- 修正offset计算，使用实际数组长度

src/views/conversationHistoryBar.ts

@@ -303,6 +303,7 @@ export function getConversationHistoryBarScript(): string {
     let totalHistory = 0;
     let hasMoreHistory = false;
     let isLoadingHistory = false;
+    let currentLoadRequestId = 0;  // 请求 ID，用于防止并发加载
     const HISTORY_PAGE_SIZE = 10;
     const MAX_HISTORY_ITEMS = 100;
 
@@ -346,11 +347,15 @@ export function getConversationHistoryBarScript(): string {
         return;
       }
 
+      // 生成新的请求 ID，用于防止并发加载
+      const requestId = ++currentLoadRequestId;
+
       isLoadingHistory = true;
       vscode.postMessage({
         command: 'loadConversationHistory',
         offset: currentOffset,
-        limit: HISTORY_PAGE_SIZE
+        limit: HISTORY_PAGE_SIZE,
+        requestId: requestId
       });
     }
 
@@ -362,11 +367,19 @@ export function getConversationHistoryBarScript(): string {
         return;
       }
 
-      // 追加新数据
+      // 追加新数据（去重）
-      conversationHistory = conversationHistory.concat(data.items);
+      const existingIds = new Set(conversationHistory.map(item => item.id));
+      const newItems = [];
+      for (const item of data.items) {
+        if (!existingIds.has(item.id)) {
+          existingIds.add(item.id);
+          newItems.push(item);
+        }
+      }
+      conversationHistory = conversationHistory.concat(newItems);
       totalHistory = data.total;
       hasMoreHistory = data.hasMore;
-      currentOffset += data.items.length;
+      currentOffset = conversationHistory.length;
 
       const historyList = document.getElementById('historyList');
       if (!historyList) {
@@ -454,9 +467,10 @@ export function getConversationHistoryBarScript(): string {
       });
     }
 
-    // 监听下拉菜单滚动事件
+    // 监听下拉菜单滚动事件（防止重复注册）
     const historyDropdownMenu = document.getElementById('historyDropdownMenu');
-    if (historyDropdownMenu) {
+    if (historyDropdownMenu && !historyDropdownMenu._scrollListenerAdded) {
+      historyDropdownMenu._scrollListenerAdded = true;
       historyDropdownMenu.addEventListener('scroll', () => {
         const menu = historyDropdownMenu;
         const scrollTop = menu.scrollTop;