feat: 饮食记录逻辑重构 + 通知管理分隔线修复 + 多页面 UI 调整

- 饮食: 新增 DietCommentaryPolicy + diet_record_logic, 饮食记录逻辑抽取复用
- 通知管理: 分隔线改为仿通知中心样式, 跳过图标区域只留文字下方
- 侧边栏: 对话记录操作栏浮层修复 + 常用功能间距收紧
- 智能体: 欢迎卡片去 400ms 延迟 + 胶囊去阴影
- 后端: AI 会话仓库新增方法 + 饮食评论策略 + 健康记录规则调整
- 其他: api_client IP 适配 + 多页面 UI 微调 + 新增测试

health_app/lib/widgets/health_drawer.dart

@@ -380,25 +380,25 @@ class _NavigationSection extends StatelessWidget {
         icon: LucideIcons.folderHeart,
         title: '档案',
         route: 'healthArchive',
-        colors: const [Color(0xFF93C5FD), Color(0xFF60A5FA)],
+        colors: AppColors.healthGradient.colors,
       ),
       _NavItem(
         icon: LucideIcons.fileText,
         title: '报告',
         route: 'reports',
-        colors: const [Color(0xFFBFDBFE), Color(0xFF93C5FD)],
+        colors: AppColors.reportGradient.colors,
       ),
       _NavItem(
         icon: LucideIcons.pill,
         title: '用药',
         route: 'medications',
-        colors: const [Color(0xFFDDD6FE), Color(0xFFC4B5FD)],
+        colors: AppColors.medicationGradient.colors,
       ),
       _NavItem(
         icon: LucideIcons.utensils,
         title: '饮食',
         route: 'dietRecords',
-        colors: const [Color(0xFFFBCFE8), Color(0xFFF472B6)],
+        colors: AppColors.dietGradient.colors,
       ),
       _NavItem(
         icon: LucideIcons.calendarDays,
@@ -416,13 +416,13 @@ class _NavigationSection extends StatelessWidget {
         icon: LucideIcons.footprints,
         title: '运动',
         route: 'exercisePlan',
-        colors: const [Color(0xFFA5F3FC), Color(0xFF67E8F9)],
+        colors: AppColors.exerciseGradient.colors,
       ),
       _NavItem(
         icon: LucideIcons.bluetooth,
         title: '设备',
         route: 'devices',
-        colors: const [Color(0xFF60A5FA), Color(0xFFC4B5FD)],
+        colors: AppColors.deviceGradient.colors,
       ),
     ];
 
@@ -466,14 +466,14 @@ class _NavTile extends StatelessWidget {
   };
 
   List<Color> get _colors => switch (item.route) {
-    'healthArchive' => const [AppColors.healthLight, AppColors.health],
-    'reports' => const [AppColors.reportLight, AppColors.report],
-    'medications' => const [AppColors.medicationLight, AppColors.medication],
-    'dietRecords' => const [AppColors.dietLight, AppColors.diet],
+    'healthArchive' => AppColors.healthGradient.colors,
+    'reports' => AppColors.reportGradient.colors,
+    'medications' => AppColors.medicationGradient.colors,
+    'dietRecords' => AppColors.dietGradient.colors,
     'calendar' => const [AppColors.calendarLight, AppColors.calendar],
     'followups' => const [AppColors.followupLight, AppColors.followup],
-    'exercisePlan' => const [AppColors.exerciseLight, AppColors.exercise],
-    'devices' => const [AppColors.deviceLight, AppColors.device],
+    'exercisePlan' => AppColors.exerciseGradient.colors,
+    'devices' => AppColors.deviceGradient.colors,
     _ => item.colors,
   };