feat(admin): add destination hero and region admin modules

Add new API type definitions for DestinationHero and DestinationRegion
Extend SiteConfig and SiteModule to include the new site modules
Update destination page sidebar label and structure page configuration
Add admin editor UI, payload handling, and empty draft generators for the new modules
Adjust item metadata and form fields to support the new site item types

src/components/admin/AdminShell.tsx

@@ -21,7 +21,7 @@ const sidebarGroups: { id: string; label: string; items: { id: Tab; label: strin
     label: "前台页面",
     items: [
       { id: "home", label: "小程序首页", icon: Home, description: "轮播、主题、CTA" },
-      { id: "destinations", label: "目的地页", icon: MapPin, description: "字典、搜索、商品" },
+      { id: "destinations", label: "目的地页", icon: MapPin, description: "主视觉、热门、省内" },
       { id: "products", label: "商品维护", icon: Package, description: "列表、卡片、详情" },
     ],
   },