feat: 健康仪表盘配色调整 + 登录页品牌升级 + iOS 配置 + 隐私文案修订 + 文档清理

## UI 配色
- 健康仪表盘: 背景从蓝紫粉三色渐变改为 #4FACFE 纯色蓝, 白字清晰不抢眼
- app_colors / app_design_tokens / app_theme: 配色体系微调
- 多个 widget 和页面跟随配色更新(health_drawer/admin_drawer/doctor_drawer/enterprise_widgets 等)

## 登录页品牌升级
- 新增品牌素材: drawer_background_v2 / login_background_v2 / health_login_character_transparent
- login_page 重构, 接入新品牌视觉
- app.dart 启动流程调整

## iOS / Android 配置
- Info.plist: 权限描述调整
- AppIcon / LaunchImage: 资源更新
- AndroidManifest: 权限微调

## 隐私文案修订
- privacy.html: 蓝牙设备描述调整为"标准蓝牙血压服务", 移除未上线设备类型表述
- terms.html: 移除"在线医生咨询"相关条款, 服务范围收窄

## 通知中心
- notification_center_page: 重构通知项布局

## 其他
- 删除已完成的计划/spec 文档(ui-system-first-pass / apple-sign-in / secondary-page-color-refresh / notification-preferences-design / ui-design-system)
- 新增 native_navigation_test
- 新增 HANDOFF 交接文档
- home_message_order_test 更新
- .gitignore 调整

health_app/lib/pages/home/widgets/chat_messages_view.dart

@@ -231,7 +231,7 @@ class ChatMessagesView extends ConsumerWidget {
                               info.$2,
                               style: AppTextStyles.chatTitle.copyWith(
                                 fontSize: 22,
-                                fontWeight: FontWeight.w900,
+                                fontWeight: FontWeight.w700,
                               ),
                             ),
                             const SizedBox(height: 8),
@@ -692,7 +692,7 @@ class ChatMessagesView extends ConsumerWidget {
                                       text: mainValue,
                                       style: TextStyle(
                                         fontSize: 36,
-                                        fontWeight: FontWeight.w800,
+                                        fontWeight: FontWeight.w600,
                                         color: abnormal
                                             ? AppColors.error
                                             : AppColors.textPrimary,
@@ -886,7 +886,7 @@ class ChatMessagesView extends ConsumerWidget {
                                   '确认录入',
                                   style: TextStyle(
                                     fontSize: 18,
-                                    fontWeight: FontWeight.w800,
+                                    fontWeight: FontWeight.w600,
                                     color: AppColors.textPrimary,
                                   ),
                                 ),
@@ -1416,7 +1416,7 @@ class ChatMessagesView extends ConsumerWidget {
                   '今日健康',
                   style: TextStyle(
                     fontSize: 16,
-                    fontWeight: FontWeight.w800,
+                    fontWeight: FontWeight.w600,
                     color: AppColors.textPrimary,
                   ),
                 ),
@@ -1570,8 +1570,7 @@ class ChatMessagesView extends ConsumerWidget {
           '健康指标',
           trailing: trailing,
           status: 'warning',
-          iconColor: AppColors.warning,
-          iconBg: AppColors.warningLight,
+          iconGradient: AppModuleVisuals.health.gradient,
           onTap: () => pushRoute(ref, 'trend'),
         ),
       );
@@ -1586,6 +1585,7 @@ class ChatMessagesView extends ConsumerWidget {
           status: 'done',
           iconColor: healthIconColor,
           iconBg: healthIconBg,
+          iconGradient: AppModuleVisuals.health.gradient,
           onTap: () => pushRoute(ref, 'trend'),
         ),
       );
@@ -1625,6 +1625,7 @@ class ChatMessagesView extends ConsumerWidget {
                     : (now.hour >= 18 ? 'overdue' : 'pending'),
                 iconColor: exIconColor,
                 iconBg: exIconBg,
+                iconGradient: AppModuleVisuals.exercise.gradient,
                 onTap: () => pushRoute(ref, 'exercisePlan'),
               ),
             );
@@ -1642,6 +1643,7 @@ class ChatMessagesView extends ConsumerWidget {
             status: 'pending',
             iconColor: exIconColor,
             iconBg: exIconBg,
+            iconGradient: AppModuleVisuals.exercise.gradient,
             onTap: () => pushRoute(ref, 'exercisePlan'),
           ),
         );
@@ -1657,6 +1659,7 @@ class ChatMessagesView extends ConsumerWidget {
             status: 'overdue',
             iconColor: exIconColor,
             iconBg: exIconBg,
+            iconGradient: AppModuleVisuals.exercise.gradient,
             onTap: () => pushRoute(ref, 'exercisePlan'),
           ),
         );
@@ -1672,6 +1675,7 @@ class ChatMessagesView extends ConsumerWidget {
           status: 'pending',
           iconColor: exIconColor,
           iconBg: exIconBg,
+          iconGradient: AppModuleVisuals.exercise.gradient,
           onTap: () => pushRoute(ref, 'exercisePlan'),
         ),
       );
@@ -1690,12 +1694,13 @@ class ChatMessagesView extends ConsumerWidget {
           tasks.add(
             _taskRow(
               context,
-              LucideIcons.pill,
+              AppModuleVisuals.medication.icon,
               '用药',
               trailing: meds.isEmpty ? '暂无用药安排' : '暂时不用吃药',
               status: 'done',
               iconColor: medIconColor,
               iconBg: medIconBg,
+              iconGradient: AppModuleVisuals.medication.gradient,
               onTap: () => pushRoute(ref, 'medCheckIn'),
             ),
           );
@@ -1748,12 +1753,13 @@ class ChatMessagesView extends ConsumerWidget {
         tasks.add(
           _taskRow(
             context,
-            LucideIcons.pill,
+            AppModuleVisuals.medication.icon,
             title,
             trailing: trailing,
             status: status,
             iconColor: medIconColor,
             iconBg: medIconBg,
+            iconGradient: AppModuleVisuals.medication.gradient,
             onTap: () => pushRoute(ref, 'medCheckIn'),
           ),
         );
@@ -1788,7 +1794,7 @@ class ChatMessagesView extends ConsumerWidget {
                   '今日健康',
                   style: TextStyle(
                     fontSize: 16,
-                    fontWeight: FontWeight.w800,
+                    fontWeight: FontWeight.w600,
                     color: AppColors.textPrimary,
                     height: 1.15,
                   ),
@@ -1835,10 +1841,11 @@ class ChatMessagesView extends ConsumerWidget {
     VoidCallback? onTap,
     Color? iconColor,
     Color? iconBg,
+    LinearGradient? iconGradient,
   }) {
     final colors = {
       'done': AppTheme.success,
-      'warning': AppColors.warning,
+      'warning': const Color(0xFFE8562A),
       'pending': AppColors.textHint,
       'overdue': AppTheme.error,
     };
@@ -1852,7 +1859,7 @@ class ChatMessagesView extends ConsumerWidget {
     final ibg = iconBg ?? AppTheme.primaryLight;
     final textColor = switch (status) {
       'overdue' => AppColors.error,
-      'warning' => AppColors.warning,
+      'warning' => const Color(0xFFE8562A),
       _ => AppColors.textPrimary,
     };
     return Padding(
@@ -1871,10 +1878,15 @@ class ChatMessagesView extends ConsumerWidget {
                   width: 32,
                   height: 32,
                   decoration: BoxDecoration(
-                    color: ibg,
+                    color: iconGradient == null ? ibg : null,
+                    gradient: iconGradient,
                     borderRadius: AppRadius.smBorder,
                   ),
-                  child: Icon(icon, size: 18, color: ic),
+                  child: Icon(
+                    icon,
+                    size: 18,
+                    color: iconGradient == null ? ic : Colors.white,
+                  ),
                 ),
                 const SizedBox(width: 10),
                 Expanded(