feat: 完成 Flutter 版智能电网 IoT 管理应用初始化搭建

lib/app/tabs_page.dart

@@ -0,0 +1,52 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+import '../core/theme/app_colors.dart';
+import '../features/customer/presentation/customer_tab.dart';
+import '../features/mine/presentation/mine_tab.dart';
+import '../features/project/presentation/project_tab.dart';
+import '../features/workbench/presentation/workbench_tab.dart';
+import '../shared/widgets/x_bottom_nav.dart';
+import 'tab_index.dart';
+
+/// 4 个 Tab 的常驻容器，对应 `pages/tabs/index.vue`。
+///
+/// 源项目用 `v-show` 切换，不销毁重建、保留滚动位置与内部状态；
+/// 这里用 [IndexedStack] 达到同样效果。
+class TabsPage extends ConsumerWidget {
+  const TabsPage({super.key});
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    final current = ref.watch(tabIndexProvider);
+
+    return Scaffold(
+      backgroundColor: AppColors.bgPage,
+      body: Stack(
+        children: [
+          Positioned.fill(
+            child: IndexedStack(
+              index: current.index,
+              children: const [
+                WorkbenchTab(),
+                CustomerTab(),
+                ProjectTab(),
+                MineTab(),
+              ],
+            ),
+          ),
+          Positioned(
+            left: 0,
+            right: 0,
+            bottom: 0,
+            child: XBottomNav(
+              current: current.key,
+              onChanged: (key) =>
+                  ref.read(tabIndexProvider.notifier).selectByKey(key),
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+}