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/core/app_colors.dart

@@ -20,15 +20,15 @@ class AppColors {
   static const Color meadowAccent = Color(0xFFBAE6FD);
   static const Color sageAccent = Color(0xFFE9D5FF);
 
-  static const Color health = Color(0xFF34D399);
-  static const Color healthLight = Color(0xFFF0FDF7);
-  static const Color healthBorder = Color(0xFFC8F7E1);
+  static const Color health = Color(0xFF2D9D8F);
+  static const Color healthLight = Color(0xFFECF8F5);
+  static const Color healthBorder = Color(0xFFCBE9E2);
   static const Color medication = Color(0xFF00B8D9);
   static const Color medicationLight = Color(0xFFEAFBFF);
   static const Color medicationBorder = Color(0xFFB8F0FA);
-  static const Color exercise = Color(0xFF4F7DD9);
-  static const Color exerciseLight = Color(0xFFEFF4FF);
-  static const Color exerciseBorder = Color(0xFFD5E2FF);
+  static const Color exercise = Color(0xFF566FD4);
+  static const Color exerciseLight = Color(0xFFF1F3FD);
+  static const Color exerciseBorder = Color(0xFFD7DCF6);
   static const Color report = Color(0xFF6366F1);
   static const Color reportLight = Color(0xFFEFFBFF);
   static const Color reportBorder = Color(0xFFBAE6FD);
@@ -51,7 +51,7 @@ class AppColors {
   static const Color followupLight = Color(0xFFFDF2F8);
   static const Color followupBorder = Color(0xFFFBCFE8);
 
-  static const Color background = Color(0xFFF7F8FA);
+  static const Color background = Color(0xFFF3F5F8);
   static const Color backgroundSoft = Color(0xFFFFFFFF);
   static const Color cardBackground = Color(0xFFFFFFFF);
   static const Color cardInner = Color(0xFFF1F5F9);
@@ -168,7 +168,7 @@ class AppColors {
   static const LinearGradient healthGradient = LinearGradient(
     begin: Alignment.centerLeft,
     end: Alignment.centerRight,
-    colors: [Color(0xFF6EE7B7), Color(0xFF67E8F9)],
+    colors: [Color(0xFF2FAE9B), Color(0xFF63BFAE)],
   );
 
   static const LinearGradient medicationGradient = LinearGradient(
@@ -180,7 +180,7 @@ class AppColors {
   static const LinearGradient exerciseGradient = LinearGradient(
     begin: Alignment.topLeft,
     end: Alignment.bottomRight,
-    colors: [Color(0xFFE0C3FC), Color(0xFF8EC5FC)],
+    colors: [Color(0xFF5B7CDE), Color(0xFF7569D9)],
   );
 
   static const LinearGradient reportGradient = LinearGradient(

health_app/lib/core/app_design_tokens.dart

@@ -75,13 +75,13 @@ class AppTextStyles {
 
   static const TextStyle appBarTitle = TextStyle(
     fontSize: 19,
-    fontWeight: FontWeight.w800,
+    fontWeight: FontWeight.w700,
     color: AppColors.textPrimary,
   );
 
   static const TextStyle summaryTitle = TextStyle(
     fontSize: 20,
-    fontWeight: FontWeight.w900,
+    fontWeight: FontWeight.w700,
     color: AppColors.textPrimary,
     height: 1.2,
   );
@@ -95,13 +95,13 @@ class AppTextStyles {
 
   static const TextStyle sectionTitle = TextStyle(
     fontSize: 18,
-    fontWeight: FontWeight.w800,
+    fontWeight: FontWeight.w600,
     color: AppColors.textPrimary,
   );
 
   static const TextStyle listTitle = TextStyle(
     fontSize: 18,
-    fontWeight: FontWeight.w800,
+    fontWeight: FontWeight.w600,
     color: AppColors.textPrimary,
     height: 1.22,
   );
@@ -122,7 +122,7 @@ class AppTextStyles {
 
   static const TextStyle formLabel = TextStyle(
     fontSize: 15,
-    fontWeight: FontWeight.w700,
+    fontWeight: FontWeight.w600,
     color: AppColors.textSecondary,
   );
 
@@ -134,19 +134,19 @@ class AppTextStyles {
 
   static const TextStyle tag = TextStyle(
     fontSize: 13,
-    fontWeight: FontWeight.w800,
+    fontWeight: FontWeight.w600,
     color: AppColors.textSecondary,
     height: 1.15,
   );
 
   static const TextStyle button = TextStyle(
     fontSize: 16,
-    fontWeight: FontWeight.w800,
+    fontWeight: FontWeight.w600,
   );
 
   static const TextStyle miniButton = TextStyle(
     fontSize: 14,
-    fontWeight: FontWeight.w800,
+    fontWeight: FontWeight.w600,
   );
 
   static const TextStyle chatBody = TextStyle(
@@ -158,7 +158,7 @@ class AppTextStyles {
   static const TextStyle chatTitle = TextStyle(
     fontSize: 20,
     height: 1.35,
-    fontWeight: FontWeight.w800,
+    fontWeight: FontWeight.w700,
     color: AppColors.textPrimary,
   );
 

health_app/lib/core/app_theme.dart

@@ -678,7 +678,7 @@ class AppTheme {
       surfaceTintColor: Colors.transparent,
       titleTextStyle: TextStyle(
         fontSize: 20,
-        fontWeight: FontWeight.w800,
+        fontWeight: FontWeight.w700,
         color: text,
       ),
       toolbarHeight: 52,
@@ -724,7 +724,7 @@ class AppTheme {
         foregroundColor: Colors.white,
         minimumSize: const Size(double.infinity, 50),
         shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(rLg)),
-        textStyle: const TextStyle(fontSize: 16, fontWeight: FontWeight.w700),
+        textStyle: const TextStyle(fontSize: 16, fontWeight: FontWeight.w600),
         elevation: 0,
       ),
     ),
@@ -753,12 +753,12 @@ class AppTheme {
     textTheme: const TextTheme(
       headlineLarge: TextStyle(
         fontSize: 24,
-        fontWeight: FontWeight.w800,
+        fontWeight: FontWeight.w700,
         color: text,
       ),
       titleLarge: TextStyle(
         fontSize: 18,
-        fontWeight: FontWeight.w700,
+        fontWeight: FontWeight.w600,
         color: text,
       ),
       titleMedium: TextStyle(