feat: 二级页面色彩刷新 + 用药/通知/设备重构 + 后端健康档案/通知管线增强 + 大量测试

## 后端
- 健康档案: 新增手术状态字段 + EF 迁移; HealthArchiveService 新增查询方法
- 健康记录: HealthRecordService 新增批量/统计方法; 契约扩展
- 用药: 新增 MedicationScheduleStatus 枚举; MedicationService 排班逻辑调整
- 通知: EfUserNotificationPipeline 重构; 新增 EfReminderCatchUpService; 通知管线支持更多场景
- 用户: UserService 账号删除逻辑; 新增 local_account_file_cleanup; EfUserRepository 扩展
- AI: medication_agent_handler 微调; prompt_manager 优化; AiConversationService 上下文处理
- Endpoint: doctor/medication/exercise/health/notification/user 等多接口调整
- BackgroundService: health_record_reminder_service 重构, 提醒补漏逻辑
- 测试: 新增 account_deletion/doctor_endpoint/medication_schedule/medication_update/prompt_manager 测试

## 前端
- UI 系统: app_theme 大幅重构; app_colors/app_design_tokens/app_module_visuals 调整; 二级页面色彩刷新
- 主页: home_page 背景渐变 + 消息列表提取 _HomeMessages + 通知检查逻辑; chat_messages_view 全面重构
- 用药: medication_list/edit/checkin 三页重构, 新增 medication_ui_logic 抽取
- 通知: notification_prefs_page 重构, 新增 notification_prefs_logic; notification_center 优化
- 设备: device_management 重构, 新增 device_sync_ui_logic; device_scan 优化
- 趋势图: trend_page 大幅重构
- 登录: login_page 重构
- 个人资料: 新增 profile_edit_page; profile_page 优化
- 运动: 新增 exercise/ 目录 + care_plan_ui_logic
- 其他: remaining_pages/report_pages/health_drawer/admin/doctor 等多页面调整
- 组件: common_widgets/app_empty_state/app_error_state/app_future_view/app_toast/ai_content 优化
- Provider: chat_provider/consultation_provider/data_providers/auth_provider 调整
- AndroidManifest: 移除多余权限
- 测试: 新增 ai_content/care_plan/home_message/login_flow/medication_checkin/medication_ui/notification_prefs/profile_device/secondary_page/swipe_delete 等大量测试

## 文档
- 新增 ui-design-system.md 设计系统文档
- 新增 secondary-page-color-refresh 计划 + specs 目录

health_app/lib/widgets/enterprise_widgets.dart

@@ -39,9 +39,7 @@ class EnterpriseHeader extends StatelessWidget {
       padding: AppSpacing.panel,
       decoration: BoxDecoration(
         color: Colors.white,
-        borderRadius: AppRadius.xlBorder,
-        border: Border.all(color: AppColors.border, width: 1.1),
-        boxShadow: AppShadows.soft,
+        borderRadius: AppRadius.lgBorder,
       ),
       child: Column(
         crossAxisAlignment: CrossAxisAlignment.start,
@@ -50,17 +48,13 @@ class EnterpriseHeader extends StatelessWidget {
             children: [
               if (showIcon) ...[
                 Container(
-                  width: 46,
-                  height: 46,
+                  width: 42,
+                  height: 42,
                   decoration: BoxDecoration(
-                    gradient: LinearGradient(
-                      begin: Alignment.topLeft,
-                      end: Alignment.bottomRight,
-                      colors: [color, accent],
-                    ),
-                    borderRadius: BorderRadius.circular(14),
+                    color: color.withValues(alpha: 0.10),
+                    borderRadius: AppRadius.smBorder,
                   ),
-                  child: Icon(icon, color: Colors.white, size: 25),
+                  child: Icon(icon, color: color, size: 22),
                 ),
                 const SizedBox(width: 12),
               ],
@@ -96,7 +90,6 @@ class EnterpriseHeader extends StatelessWidget {
                     child: _HeaderStat(
                       stat: stats[i],
                       color: i.isEven ? color : accent,
-                      accent: i.isEven ? accent : color,
                     ),
                   ),
                   if (i != stats.length - 1) const SizedBox(width: 8),
@@ -113,13 +106,8 @@ class EnterpriseHeader extends StatelessWidget {
 class _HeaderStat extends StatelessWidget {
   final EnterpriseStat stat;
   final Color color;
-  final Color accent;
 
-  const _HeaderStat({
-    required this.stat,
-    required this.color,
-    required this.accent,
-  });
+  const _HeaderStat({required this.stat, required this.color});
 
   @override
   Widget build(BuildContext context) {
@@ -127,16 +115,8 @@ class _HeaderStat extends StatelessWidget {
       constraints: const BoxConstraints(minHeight: 66),
       padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 11),
       decoration: BoxDecoration(
-        gradient: LinearGradient(
-          begin: Alignment.topLeft,
-          end: Alignment.bottomRight,
-          colors: [
-            color.withValues(alpha: 0.10),
-            accent.withValues(alpha: 0.06),
-          ],
-        ),
+        color: const Color(0xFFF7F8FA),
         borderRadius: AppRadius.smBorder,
-        border: Border.all(color: AppColors.borderLight, width: 1.1),
       ),
       child: Row(
         children: [