feat(ui): 添加编辑器和文件浏览器状态持久化

- FileExplorer: 保存展开的目录路径到 localStorage
- IDE: 保存打开的标签页和活动标签，刷新后自动恢复
- App: 调整 IDE 面板默认宽度为 70%

packages/ui/src/components/FileExplorer.tsx

@@ -132,11 +132,21 @@ function TreeNode({ node, depth, onFileSelect, expandedPaths, onToggleExpand }:
   );
 }
 
+const STORAGE_KEY_EXPANDED = 'ai-assistant-file-explorer-expanded';
+
 export function FileExplorer({ onFileSelect, className, workingDirectory }: FileExplorerProps) {
   const [tree, setTree] = useState<FileTreeNode[]>([]);
   const [loading, setLoading] = useState(true);
   const [error, setError] = useState<string | null>(null);
-  const [expandedPaths, setExpandedPaths] = useState<Set<string>>(new Set());
+  // 从 localStorage 恢复展开状态
+  const [expandedPaths, setExpandedPaths] = useState<Set<string>>(() => {
+    try {
+      const saved = localStorage.getItem(STORAGE_KEY_EXPANDED);
+      return saved ? new Set(JSON.parse(saved)) : new Set();
+    } catch {
+      return new Set();
+    }
+  });
 
   // 加载文件树
   const loadTree = useCallback(async () => {
@@ -146,13 +156,7 @@ export function FileExplorer({ onFileSelect, className, workingDirectory }: File
       const result = await getFileTree('.', 4);
       if (result.success) {
         setTree(result.data.tree);
-        // 默认展开第一层
-        const firstLevel = new Set(
-          result.data.tree
-            .filter((n) => n.type === 'directory')
-            .map((n) => n.path)
-        );
-        setExpandedPaths(firstLevel);
+        // 保持已保存的展开状态（不重置）
       } else {
         setError('Failed to load file tree');
       }
@@ -175,6 +179,8 @@ export function FileExplorer({ onFileSelect, className, workingDirectory }: File
       } else {
         next.add(path);
       }
+      // 保存到 localStorage
+      localStorage.setItem(STORAGE_KEY_EXPANDED, JSON.stringify([...next]));
       return next;
     });
   }, []);

packages/ui/src/components/IDE.tsx

@@ -4,13 +4,23 @@
  * 整合文件浏览器和代码编辑器的 IDE 组件
  */
 
-import { useState, useCallback, useEffect } from 'react';
+import { useState, useCallback, useEffect, useRef } from 'react';
 import { toast } from 'sonner';
 import { cn } from '../utils/cn.js';
 import { readFile, getWorkingDirectory } from '../api/client.js';
 import { FileExplorer } from './FileExplorer.js';
 import { CodeEditor, getLanguageFromFilename, type EditorTab } from './CodeEditor.js';
 
+// localStorage 键名
+const STORAGE_KEY_TABS = 'ai-assistant-editor-tabs';
+const STORAGE_KEY_ACTIVE_TAB = 'ai-assistant-editor-active-tab';
+
+// 保存的标签页格式（只保存路径，不保存内容）
+interface SavedTab {
+  path: string;
+  name: string;
+}
+
 interface IDEProps {
   className?: string;
   /** 文件浏览器宽度 */
@@ -21,6 +31,8 @@ export function IDE({ className, sidebarWidth = 256 }: IDEProps) {
   const [tabs, setTabs] = useState<EditorTab[]>([]);
   const [activeTabId, setActiveTabId] = useState<string | null>(null);
   const [workingDirectory, setWorkingDirectory] = useState<string>('');
+  const isRestoringTabs = useRef(false);
+  const hasRestoredTabs = useRef(false);
 
   // 获取工作目录
   useEffect(() => {
@@ -35,6 +47,93 @@ export function IDE({ className, sidebarWidth = 256 }: IDEProps) {
       });
   }, []);
 
+  // 从 localStorage 恢复标签页
+  useEffect(() => {
+    if (hasRestoredTabs.current) return;
+    hasRestoredTabs.current = true;
+
+    const restoreTabs = async () => {
+      try {
+        const savedTabsJson = localStorage.getItem(STORAGE_KEY_TABS);
+        const savedActivePath = localStorage.getItem(STORAGE_KEY_ACTIVE_TAB);
+
+        if (!savedTabsJson) return;
+
+        const savedTabs: SavedTab[] = JSON.parse(savedTabsJson);
+        if (savedTabs.length === 0) return;
+
+        isRestoringTabs.current = true;
+
+        // 逐个恢复标签页
+        const restoredTabs: EditorTab[] = [];
+        for (const savedTab of savedTabs) {
+          try {
+            const result = await readFile(savedTab.path);
+            if (result.success && result.data.encoding === 'utf-8') {
+              restoredTabs.push({
+                id: `tab-${Date.now()}-${restoredTabs.length}`,
+                path: savedTab.path,
+                name: savedTab.name,
+                content: result.data.content,
+                originalContent: result.data.content,
+                language: getLanguageFromFilename(savedTab.name),
+              });
+            }
+          } catch {
+            // 文件可能已删除，跳过
+          }
+        }
+
+        if (restoredTabs.length > 0) {
+          setTabs(restoredTabs);
+
+          // 恢复活动标签
+          if (savedActivePath) {
+            const activeTab = restoredTabs.find((tab) => tab.path === savedActivePath);
+            if (activeTab) {
+              setActiveTabId(activeTab.id);
+            } else {
+              setActiveTabId(restoredTabs[0].id);
+            }
+          } else {
+            setActiveTabId(restoredTabs[0].id);
+          }
+        }
+
+        isRestoringTabs.current = false;
+      } catch {
+        isRestoringTabs.current = false;
+      }
+    };
+
+    restoreTabs();
+  }, []);
+
+  // 保存标签页到 localStorage
+  useEffect(() => {
+    // 恢复过程中不保存
+    if (isRestoringTabs.current) return;
+
+    const tabsToSave: SavedTab[] = tabs.map((tab) => ({
+      path: tab.path,
+      name: tab.name,
+    }));
+    localStorage.setItem(STORAGE_KEY_TABS, JSON.stringify(tabsToSave));
+  }, [tabs]);
+
+  // 保存活动标签到 localStorage
+  useEffect(() => {
+    // 恢复过程中不保存
+    if (isRestoringTabs.current) return;
+
+    const activeTab = tabs.find((tab) => tab.id === activeTabId);
+    if (activeTab) {
+      localStorage.setItem(STORAGE_KEY_ACTIVE_TAB, activeTab.path);
+    } else {
+      localStorage.removeItem(STORAGE_KEY_ACTIVE_TAB);
+    }
+  }, [activeTabId, tabs]);
+
   // 打开文件
   const handleFileSelect = useCallback(async (path: string, name: string) => {
     // 检查是否已打开

packages/web/src/App.tsx

@@ -42,7 +42,7 @@ export function App() {
   // IDE 面板宽度（百分比）
   const [idePanelWidth, setIdePanelWidth] = useState(() => {
     const saved = localStorage.getItem('ai-assistant-ide-width');
-    return saved ? parseFloat(saved) : 60;
+    return saved ? parseFloat(saved) : 70;
   });
 
   // 初始化：加载会话