feat(layout): 重构布局组件体系与数据层

- 重构 Header 导航、Footer 页脚、MobileMenu 移动端菜单
- 新增 MobileTabBar 移动端底部导航栏
- 更新 MegaDropdown 大型下拉导航
- 重构 SEO 结构化数据组件
- 更新数据层常量 (products, services, solutions, navigation 等)
- 新增 useCountUp 数字递增 Hook
- 修复 .gitignore 中 src/lib 被错误忽略的问题

src/components/layout/mobile-menu.test.tsx

@@ -7,6 +7,27 @@ jest.mock('@/hooks/use-focus-trap', () => ({
   useFocusTrap: () => ({ current: null }),
 }));
 
+jest.mock('@/lib/site-config', () => ({
+  useSiteConfig: () => ({
+    mainNav: [
+      { id: 'products', label: '产品', href: '/products', hasDropdown: true, dropdownKey: 'products' },
+      { id: 'solutions', label: '解决方案', href: '/solutions', hasDropdown: true, dropdownKey: 'solutions' },
+      { id: 'services', label: '服务', href: '/services' },
+      { id: 'about', label: '关于我们', href: '/about' },
+      { id: 'contact', label: '联系我们', href: '/contact' },
+    ],
+    megaDropdown: {
+      products: [
+        { id: 'erp', title: 'ERP 管理系统', description: '财务·采购·销售·库存·生产', href: '/products/erp' },
+      ],
+      solutions: [
+        { id: 'manufacturing', title: '制造业', description: '智能制造·MES·质量管控', href: '/solutions/manufacturing' },
+      ],
+    },
+  }),
+  SiteConfigProvider: ({ children }: { children: React.ReactNode }) => <>{children}</>,
+}));
+
 jest.mock('@/lib/constants', () => ({
   NAVIGATION_V2: [
     { id: 'products', label: '产品', href: '/products', hasDropdown: true, dropdownKey: 'products' },