feat(home): 添加外部链接支持并优化网格布局

- 实现外部链接功能，支持在新标签页打开外部URL
- 将网格布局改为弹性布局，提升响应式显示效果
- 为卡片组件添加固定宽度，优化不同屏幕尺寸下的显示
- 重构导航逻辑，区分内部路由和外部链接跳转方式

frontend/src/pages/Home/Home.tsx

@@ -130,12 +130,18 @@ export default function WelcomePage() {
           <h2 className="text-3xl font-bold text-center text-gray-900 mb-12">
             功能模块
           </h2>
-          <div className="grid md:grid-cols-2 lg:grid-cols-4 gap-6">
+          <div className="flex flex-wrap justify-center gap-6">
             {menuItems.map((item) => (
               <Card
                 key={item.id}
-                onClick={() => navigate(item.children ? `/data/${item.children[0].id}`: `/data/${item.id}`)}
-                className="cursor-pointer hover:shadow-lg transition-all duration-200 border-0 shadow-md relative overflow-hidden group"
+                onClick={() => {
+                  if (item.externalLink) {
+                    window.open(item.externalLink, "_blank");
+                    return;
+                  }
+                  navigate(item.children ? `/data/${item.children[0].id}`: `/data/${item.id}`);
+                }}
+                className="cursor-pointer hover:shadow-lg transition-all duration-200 border-0 shadow-md relative overflow-hidden group w-full md:w-[calc(50%-12px)] lg:w-[280px]"
               >
                 <div className="text-center relative">
                   <div