feat: 三端抽屉重构 + 配色系统更新 + 后台管理页精调 + 键盘抬起组件

## 抽屉重构
- admin_drawer / doctor_drawer / health_drawer 三端抽屉全部重做
- drawer_shell 增强

## 配色系统
- app_colors / app_module_visuals / app_theme 更新
- app.dart 启动流程调整

## 后台管理页
- admin_doctors_page 大幅重构(+251)
- admin_home / doctor_dashboard / doctor_reports / doctor_home / doctor_followups / doctor_settings 精调

## 患者端
- home_page / chat_messages_view / medication_list / notification_center / remaining_pages / exercise_plan / device / diet / consultation 微调

## 新增
- keyboard_lift.dart: 键盘抬起处理组件
- AGENTS.md: agent 指引文档

## 其他
- api_client IP 适配
- app_future_view 增强
- data_providers 调整
- secondary_page_visuals_test 更新

health_app/lib/app.dart

@@ -74,11 +74,28 @@ class _BootGateState extends ConsumerState<_BootGate> {
   @override
   void initState() {
     super.initState();
+    _startTimeout();
+  }
+
+  void _startTimeout() {
+    _timer?.cancel();
     _timer = Timer(const Duration(seconds: 8), () {
       if (mounted) setState(() => _timedOut = true);
     });
   }
 
+  void _handleReadyChanged(bool? previous, bool ready) {
+    if (ready) {
+      _timer?.cancel();
+      if (_timedOut) setState(() => _timedOut = false);
+      return;
+    }
+    if (previous != false) {
+      if (_timedOut) setState(() => _timedOut = false);
+      _startTimeout();
+    }
+  }
+
   @override
   void dispose() {
     _timer?.cancel();
@@ -87,6 +104,7 @@ class _BootGateState extends ConsumerState<_BootGate> {
 
   @override
   Widget build(BuildContext context) {
+    ref.listen<bool>(appReadyProvider, _handleReadyChanged);
     final ready = ref.watch(appReadyProvider) || _timedOut;
     return Stack(
       children: [
@@ -135,9 +153,21 @@ class _RootNavigator extends ConsumerWidget {
     }
 
     return PopScope(
-      canPop: stack.length <= 1,
+      canPop: false,
       onPopInvokedWithResult: (didPop, result) {
-        if (!didPop) popRoute(ref);
+        if (didPop) return;
+        if (stack.length > 1) {
+          popRoute(ref);
+          return;
+        }
+        final homeRoute = switch (authState.user?.role) {
+          'Admin' => 'adminHome',
+          'Doctor' => 'doctorHome',
+          _ => 'home',
+        };
+        if (current.name != homeRoute && authState.isLoggedIn) {
+          goRoute(ref, homeRoute);
+        }
       },
       child: Navigator(
         pages: [
@@ -148,8 +178,12 @@ class _RootNavigator extends ConsumerWidget {
               child: buildPage(stack[index], ref),
             ),
         ],
-        onDidRemovePage: (_) {
-          if (ref.read(routeStackProvider).length > 1) popRoute(ref);
+        onDidRemovePage: (page) {
+          final routes = ref.read(routeStackProvider);
+          if (routes.length <= 1) return;
+          final lastIndex = routes.length - 1;
+          final currentPageKey = ValueKey(_pageKey(routes.last, lastIndex));
+          if (page.key == currentPageKey) popRoute(ref);
         },
       ),
     );