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

types/wagtail.ts

@@ -160,3 +160,53 @@ export interface SolutionPageDetail extends SolutionPageSummary {
 export interface SimpleContentPageDetail extends WagtailPageSummary {
   body: string; // richtext HTML
 }
+
+/**
+ * 全局 Snippet 类型（apps/core/models.py）。
+ * 通过 /api/v1/custom/core/... 只读接口获取，非 Wagtail Page API。
+ */
+export interface TeamMemberValue {
+  id: number;
+  name: string;
+  role: string;
+  bio: string;
+  photo: { url: string; title: string } | null;
+}
+
+export interface TestimonialValue {
+  id: number;
+  quote: string;
+  author_name: string;
+  author_title: string;
+  author_photo: { url: string; title: string } | null;
+}
+
+export interface PartnerValue {
+  id: number;
+  name: string;
+  website_url: string;
+  logo: { url: string; title: string } | null;
+}
+
+export interface NavigationMenuItemValue {
+  label: string;
+  url: string;
+  open_in_new_tab: boolean;
+}
+
+export interface NavigationMenuValue {
+  name: string;
+  items: NavigationMenuItemValue[];
+}
+
+export interface SiteSettingsValue {
+  company_name: string;
+  contact_phone: string;
+  contact_email: string;
+  address: string;
+  icp_number: string;
+  icp_url: string;
+  wechat_account: string;
+  weibo_url: string;
+  wechat_qrcode: { url: string; title: string } | null;
+}