merge: 修复工作台导航首屏权限加载态

furniture-3d-system/src/components/layout/AppShell.tsx

@@ -195,7 +195,7 @@ function AppShellContent({ children, user }: AppShellProps) {
     )
   }
 
-  const currentUser = user === undefined ? fetchedUser ?? null : user
+  const currentUser = user === undefined ? fetchedUser : user
 
   // 移动端：workbench 路由使用底部 Tab Bar，顶部只显示简化的顶栏
   // 桌面端：保持原有布局

furniture-3d-system/src/components/layout/__tests__/AppShell.test.tsx

@@ -11,8 +11,11 @@ jest.mock('next/navigation', () => ({
 }))
 
 jest.mock('@/components/layout/AppTopNav', () => ({
-  AppTopNav: ({ variant }: { variant?: string }) => (
+  AppTopNav: ({ variant, user }: { variant?: string; user?: unknown | null }) => (
     <div data-testid="app-top-nav" data-variant={variant ?? 'default'}>
+      <span data-testid="app-top-nav-user-state">
+        {user === undefined ? 'loading' : user === null ? 'none' : 'ready'}
+      </span>
       top nav
     </div>
   ),
@@ -85,6 +88,24 @@ describe('AppShell', () => {
     expect(screen.getByText('home content')).toBeInTheDocument()
   })
 
+  it('认证加载中保持用户态为 unknown，避免首屏导航误判为受限权限', () => {
+    usePathnameMock.mockReturnValue('/')
+    const originalFetch = global.fetch
+    global.fetch = jest.fn(() => new Promise<Response>(() => undefined))
+
+    try {
+      render(
+        <AppShell>
+          <div>home content</div>
+        </AppShell>,
+      )
+
+      expect(screen.getByTestId('app-top-nav-user-state')).toHaveTextContent('loading')
+    } finally {
+      global.fetch = originalFetch
+    }
+  })
+
   it('辅助装配按资产中心工作台壳子渲染', () => {
     usePathnameMock.mockReturnValue('/assisted-assembly')