feat(entry): 建立 MVVM+data 分层骨架，接入 V2 状态管理与 Navigation 路由

entry/src/main/ets/pages/Index.ets

@@ -1,23 +1,63 @@
+import { AppColor, AppSpacing, AppButton, LoadingView, EmptyView } from 'uikit';
+import { HomeViewModel } from '../viewmodel/HomeViewModel';
+import { User } from '../model/User';
+import { AppRouter } from '../router/AppRouter';
+import { RouteMap, RouteNames } from '../router/RouteMap';
+import { StatusCard } from '../view/StatusCard';
+
+/**
+ * 首页（@Entry）：Navigation 根容器，仅编排。
+ * 演示「页面 -> ViewModel -> Repository -> Api -> HttpClient」完整链路。
+ */
 @Entry
-@Component
+@ComponentV2
 struct Index {
-  @State message: string = 'Hello World';
+  @Local pathStack: NavPathStack = new NavPathStack();
+  @Local viewModel: HomeViewModel = HomeViewModel.create();
+  @Local title: string = 'Harmony Client';
+
+  aboutToAppear(): void {
+    AppRouter.init(this.pathStack);
+    this.viewModel.load();
+  }
 
   build() {
-    RelativeContainer() {
-      Text(this.message)
-        .id('HelloWorld')
-        .fontSize($r('app.float.page_text_font_size'))
-        .fontWeight(FontWeight.Bold)
-        .alignRules({
-          center: { anchor: '__container__', align: VerticalAlign.Center },
-          middle: { anchor: '__container__', align: HorizontalAlign.Center }
-        })
-        .onClick(() => {
-          this.message = 'Welcome';
+    Navigation(this.pathStack) {
+      Column({ space: AppSpacing.md }) {
+        Text(this.title)
+          .fontSize(24)
+          .fontWeight(FontWeight.Bold)
+          .fontColor(AppColor.textPrimary)
+
+        if (this.viewModel.loading) {
+          LoadingView({ text: '加载中...' })
+        } else if (this.viewModel.error.length > 0) {
+          EmptyView({ text: this.viewModel.error })
+        } else {
+          ForEach(this.viewModel.users, (user: User) => {
+            StatusCard({ title: user.name, subtitle: user.email })
+          }, (user: User) => user.id)
+        }
+
+        AppButton({
+          text: '进入详情页',
+          onTap: () => {
+            AppRouter.push(RouteNames.DETAIL, '来自首页的参数');
+          }
         })
+      }
+      .width('100%')
+      .height('100%')
+      .padding(AppSpacing.lg)
+      .backgroundColor(AppColor.background)
     }
-    .height('100%')
-    .width('100%')
+    .navDestination(this.routeMap)
+    .mode(NavigationMode.Stack)
+    .hideTitleBar(true)
   }
-}
+
+  @Builder
+  routeMap(name: string, param: Object) {
+    RouteMap(name, param)
+  }
+}