refactor: 完成静态网站转换，移除所有 CMS 和动态功能

- 删除数据库相关代码 (src/db/)
- 删除 API 路由 (src/app/api/)
- 删除认证相关代码 (src/lib/auth/, src/providers/)
- 删除监控和安全中间件 (src/lib/security/, src/lib/monitoring/)
- 删除 hooks (use-news, use-products, use-services)
- 更新组件为静态数据源
- 添加 nginx 静态配置和部署脚本
- 添加 static-link 组件

src/components/layout/mobile-tab-bar.tsx

@@ -1,6 +1,6 @@
 'use client';
 
-import Link from 'next/link';
+import { StaticLink } from '@/components/ui/static-link';
 import { usePathname } from 'next/navigation';
 import { Home, Briefcase, Package, FileText, User } from 'lucide-react';
 import { motion } from 'framer-motion';
@@ -33,7 +33,7 @@ export function MobileTabBar() {
           const active = isActive(tab.href);
 
           return (
-            <Link
+            <StaticLink
               key={tab.id}
               href={tab.href}
               className="flex flex-col items-center justify-center flex-1 h-full relative group min-h-12"
@@ -61,7 +61,7 @@ export function MobileTabBar() {
                   />
                 )}
               </div>
-            </Link>
+            </StaticLink>
           );
         })}
       </div>