fix: 欢迎卡片UI优化 + 蓝牙录入按钮 + 多处修复

- 欢迎卡片：去掉白框圆角错位、图片满宽、按钮去箭头改圆角居中
- 渐变actionOutlineGradient改紫蓝双色循环
- 新增健康Agent"蓝牙录入"按钮→蓝牙设备页
- "查看健康情况"改名"健康概览"
- 饮食编辑框删除bug修复(控制器缓存)
- 启动脚本加adb reverse自动转发
- 登录闪屏修复

health_app/lib/pages/remaining_pages.dart

@@ -68,8 +68,7 @@ class _DietRecordListPageState extends ConsumerState<DietRecordListPage> {
   @override
   Widget build(BuildContext context) {
     if (_loading)
-      return Scaffold(
-        backgroundColor: AppColors.background,
+      return GradientScaffold(
         appBar: AppBar(
           backgroundColor: Colors.white,
           elevation: 0,
@@ -92,8 +91,7 @@ class _DietRecordListPageState extends ConsumerState<DietRecordListPage> {
       (s, r) => s + ((r['totalCalories'] as num?)?.toInt() ?? 0),
     );
 
-    return Scaffold(
-      backgroundColor: AppColors.background,
+    return GradientScaffold(
       appBar: AppBar(
         backgroundColor: Colors.white,
         elevation: 0,
@@ -1349,8 +1347,7 @@ class _HealthArchivePageState extends ConsumerState<HealthArchivePage> {
   @override
   Widget build(BuildContext context) {
     if (_loading) {
-      return Scaffold(
-        backgroundColor: AppColors.background,
+      return GradientScaffold(
         appBar: AppBar(
           backgroundColor: Colors.white,
           elevation: 0,
@@ -1367,8 +1364,7 @@ class _HealthArchivePageState extends ConsumerState<HealthArchivePage> {
         body: const Center(child: CircularProgressIndicator()),
       );
     }
-    return Scaffold(
-      backgroundColor: AppColors.background,
+    return GradientScaffold(
       appBar: AppBar(
         backgroundColor: Colors.white,
         elevation: 0,
@@ -1856,8 +1852,7 @@ class _HealthCalendarPageState extends ConsumerState<HealthCalendarPage> {
     final isToday =
         _selectedDate != null && _dateKey(_selectedDate!) == _dateKey(today);
 
-    return Scaffold(
-      backgroundColor: AppColors.background,
+    return GradientScaffold(
       appBar: AppBar(
         backgroundColor: Colors.white,
         elevation: 0,