Add end-to-end tests for workspace switching and backend tests for ask_question tool

- Implemented E2E tests for workspace switching functionality, covering scenarios such as switching workspaces, data isolation, language preference maintenance, and UI updates.
- Added tests to ensure workspace data is cleared on logout and handles unsaved changes during workspace switches.
- Created comprehensive backend tests for the ask_question tool, validating question creation, execution, answer handling, cancellation, and timeout scenarios.
- Included edge case tests to ensure robustness against duplicate questions and invalid answers.

ccw/frontend/src/components/layout/AppShell.tsx

@@ -10,7 +10,8 @@ import { Sidebar } from './Sidebar';
 import { MainContent } from './MainContent';
 import { CliStreamMonitor } from '@/components/shared/CliStreamMonitor';
 import { NotificationPanel } from '@/components/notification';
-import { useNotificationStore } from '@/stores';
+import { AskQuestionDialog } from '@/components/a2ui/AskQuestionDialog';
+import { useNotificationStore, selectCurrentQuestion } from '@/stores';
 import { useWebSocketNotifications } from '@/hooks';
 
 export interface AppShellProps {
@@ -57,6 +58,10 @@ export function AppShell({
     (state) => state.loadPersistentNotifications
   );
 
+  // Current question dialog state
+  const currentQuestion = useNotificationStore(selectCurrentQuestion);
+  const setCurrentQuestion = useNotificationStore((state) => state.setCurrentQuestion);
+
   // Initialize WebSocket notifications handler
   useWebSocketNotifications();
 
@@ -106,6 +111,10 @@ export function AppShell({
     useNotificationStore.getState().setPanelVisible(false);
   }, []);
 
+  const handleQuestionDialogClose = useCallback(() => {
+    setCurrentQuestion(null);
+  }, [setCurrentQuestion]);
+
   return (
     <div className="flex flex-col min-h-screen bg-background">
       {/* Header - fixed at top */}
@@ -150,6 +159,14 @@ export function AppShell({
         isOpen={isNotificationPanelVisible}
         onClose={handleNotificationPanelClose}
       />
+
+      {/* Ask Question Dialog - For ask_question MCP tool */}
+      {currentQuestion && (
+        <AskQuestionDialog
+          payload={currentQuestion}
+          onClose={handleQuestionDialogClose}
+        />
+      )}
     </div>
   );
 }

ccw/frontend/src/components/layout/Header.tsx

@@ -16,6 +16,7 @@ import {
   User,
   LogOut,
   Terminal,
+  Bell,
 } from 'lucide-react';
 import { cn } from '@/lib/utils';
 import { Button } from '@/components/ui/Button';
@@ -24,6 +25,7 @@ import { useTheme } from '@/hooks';
 import { LanguageSwitcher } from './LanguageSwitcher';
 import { WorkspaceSelector } from '@/components/workspace/WorkspaceSelector';
 import { useCliStreamStore, selectActiveExecutionCount } from '@/stores/cliStreamStore';
+import { useNotificationStore } from '@/stores';
 
 export interface HeaderProps {
   /** Callback to toggle mobile sidebar */
@@ -49,6 +51,13 @@ export function Header({
   const { isDark, toggleTheme } = useTheme();
   const activeCliCount = useCliStreamStore(selectActiveExecutionCount);
 
+  // Notification state for badge
+  const persistentNotifications = useNotificationStore((state) => state.persistentNotifications);
+  const togglePanel = useNotificationStore((state) => state.togglePanel);
+
+  // Calculate unread count
+  const unreadCount = persistentNotifications.filter((n) => !n.read).length;
+
   const handleRefresh = useCallback(() => {
     if (onRefresh && !isRefreshing) {
       onRefresh();
@@ -105,6 +114,23 @@ export function Header({
         {/* Workspace selector */}
         {projectPath && <WorkspaceSelector />}
 
+        {/* Notification badge */}
+        <Button
+          variant="ghost"
+          size="icon"
+          onClick={togglePanel}
+          aria-label={formatMessage({ id: 'common.aria.notifications' }) || 'Notifications'}
+          title={formatMessage({ id: 'common.aria.notifications' }) || 'Notifications'}
+          className="relative"
+        >
+          <Bell className="w-5 h-5" />
+          {unreadCount > 0 && (
+            <span className="absolute -top-1 -right-1 h-4 w-4 rounded-full bg-destructive text-[10px] text-destructive-foreground flex items-center justify-center font-medium">
+              {unreadCount > 9 ? '9+' : unreadCount}
+            </span>
+          )}
+        </Button>
+
         {/* Refresh button */}
         {onRefresh && (
           <Button