feat: 接入后端全局Snippet（导航菜单/站点设置），补充团队/证言/合作伙伴 service 层

- Header 改为异步 Server Component，接入 NavigationMenu（name=main），
  接口不可用或未配置时回退静态导航项
- Footer 改为异步 Server Component，接入 SiteSettings，
  公司名/ICP备案号/备案链接优先取后台配置，缺省回退硬编码值
- types/wagtail.ts 新增 TeamMember/Testimonial/Partner/NavigationMenu/SiteSettings 类型
- 新增 services: team/testimonial/partner/navigation/site-settings.service.ts
- lint、build 均已验证通过

components/layout/Header.tsx

@@ -1,6 +1,7 @@
 import Link from "next/link";
+import { getNavigationMenu } from "@/services/navigation.service";
 
-const navItems = [
+const fallbackNavItems = [
   { title: "首页", href: "/" },
   { title: "产品", href: "/products" },
   { title: "解决方案", href: "/solutions" },
@@ -8,7 +9,18 @@ const navItems = [
   { title: "博客", href: "/blog" },
 ];
 
-export default function Header() {
+export default async function Header() {
+  // 优先使用后台配置的主导航（apps.core.NavigationMenu，name="main"），
+  // 未配置或接口不可用时回退到静态导航项，保证构建/渲染始终可用。
+  const menu = await getNavigationMenu("main");
+  const navItems = menu?.items.length
+    ? menu.items.map((item) => ({
+        title: item.label,
+        href: item.url,
+        newTab: item.open_in_new_tab,
+      }))
+    : fallbackNavItems.map((item) => ({ ...item, newTab: false }));
+
   return (
     <header className="sticky top-0 z-50 border-b border-slate-100 bg-white/80 backdrop-blur">
       <div className="mx-auto flex h-16 max-w-7xl items-center justify-between px-6">
@@ -17,7 +29,13 @@ export default function Header() {
         </Link>
         <nav className="flex gap-8">
           {navItems.map((item) => (
-            <Link key={item.href} href={item.href} className="text-slate-700">
+            <Link
+              key={item.href}
+              href={item.href}
+              className="text-slate-700"
+              target={item.newTab ? "_blank" : undefined}
+              rel={item.newTab ? "noreferrer" : undefined}
+            >
               {item.title}
             </Link>
           ))}
@@ -26,3 +44,4 @@ export default function Header() {
     </header>
   );
 }
+