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/pages/diet/diet_capture_page.dart

@@ -378,6 +378,7 @@ class _DietCapturePageState extends ConsumerState<DietCapturePage> {
     final state = ref.watch(dietProvider);
 
     return SingleChildScrollView(
+      keyboardDismissBehavior: ScrollViewKeyboardDismissBehavior.onDrag,
       padding: const EdgeInsets.fromLTRB(16, 12, 16, 24),
       child: Column(
         crossAxisAlignment: CrossAxisAlignment.stretch,