refactor(client): SubScaffold 六合一(视觉零变化)+ tablet 注释订正 + 平板通知铃入口(#20)

client/lib/screens/invite_page.dart

@@ -16,6 +16,7 @@ import '../widgets/page_body.dart';
 import '../widgets/pangolin_button.dart';
 import '../widgets/pangolin_icons.dart';
 import '../widgets/pangolin_toast.dart';
+import '../widgets/sub_scaffold.dart';
 
 class InviteScreen extends ConsumerWidget {
   const InviteScreen({super.key, required this.t, this.onBack, this.embedded = false});
@@ -59,7 +60,6 @@ class InviteScreen extends ConsumerWidget {
 
   @override
   Widget build(BuildContext context, WidgetRef ref) {
-    final c = context.pangolin;
     final inviteAsync = ref.watch(inviteProvider);
 
     Widget body = PageBody(child: inviteAsync.when(
@@ -70,24 +70,11 @@ class InviteScreen extends ConsumerWidget {
           : _InviteContent(t: t, info: info, onCopy: _copy, onVerifyAndClaim: (ctx) => _verifyAndClaim(ctx, ref)),
     ));
 
-    if (embedded) return body;
-    return Scaffold(
-      backgroundColor: c.bg,
-      body: SafeArea(
-        child: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
-          Padding(
-            padding: const EdgeInsets.fromLTRB(8, 6, 16, 10),
-            child: Row(children: [
-              IconButton(
-                onPressed: onBack ?? () => Navigator.of(context).maybePop(),
-                icon: Icon(PangolinIcons.arrowLeft, size: 22, color: c.fg1),
-              ),
-              Text(t.inviteTitle, style: PangolinText.h3.copyWith(color: c.fg1, fontWeight: FontWeight.w700)),
-            ]),
-          ),
-          Expanded(child: body),
-        ]),
-      ),
+    return SubScaffold(
+      title: t.inviteTitle,
+      onBack: onBack,
+      embedded: embedded,
+      child: body,
     );
   }
 }

client/lib/screens/notifications_page.dart

@@ -7,9 +7,9 @@ import 'package:flutter_riverpod/flutter_riverpod.dart';
 
 import '../l10n/app_text.dart';
 import '../pangolin_theme.dart';
-import '../widgets/page_body.dart';
 import '../widgets/pangolin_icons.dart';
 import '../widgets/status_pill.dart';
+import '../widgets/sub_scaffold.dart';
 
 typedef _Notice = ({
   IconData icon,
@@ -137,24 +137,12 @@ class NotificationsScreen extends ConsumerWidget {
           ],
         );
 
-    if (embedded) return PageBody(child: content());
-    return Scaffold(
-      backgroundColor: c.bg,
-      body: SafeArea(
-        child: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
-          Padding(
-            padding: const EdgeInsets.fromLTRB(8, 6, 16, 10),
-            child: Row(children: [
-              IconButton(
-                onPressed: onBack ?? () => Navigator.of(context).maybePop(),
-                icon: Icon(PangolinIcons.arrowLeft, size: 22, color: c.fg1),
-              ),
-              Text(t.notifTitle, style: PangolinText.h3.copyWith(color: c.fg1, fontWeight: FontWeight.w700)),
-            ]),
-          ),
-          Expanded(child: PageBody(child: content())),
-        ]),
-      ),
+    return SubScaffold(
+      title: t.notifTitle,
+      onBack: onBack,
+      embedded: embedded,
+      wrapPageBody: true,
+      child: content(),
     );
   }
 }

client/lib/screens/orders_page.dart

@@ -14,6 +14,7 @@ import '../pangolin_theme.dart';
 import '../state/navigation_provider.dart';
 import '../state/orders_provider.dart';
 import '../widgets/page_body.dart';
+import '../widgets/sub_scaffold.dart';
 import '../widgets/pangolin_button.dart';
 import '../widgets/pangolin_icons.dart';
 import '../widgets/status_pill.dart';
@@ -58,38 +59,6 @@ String _fmtDateTime(DateTime d) {
   return '${l.year}-${two(l.month)}-${two(l.day)} ${two(l.hour)}:${two(l.minute)}';
 }
 
-/// 带返回栏的子页骨架(embedded=true 只返回内容,返回/标题由外层 shell 顶栏提供)。
-class _SubScaffold extends StatelessWidget {
-  const _SubScaffold({required this.title, required this.child, this.onBack, this.embedded = false});
-  final String title;
-  final Widget child;
-  final VoidCallback? onBack;
-  final bool embedded;
-  @override
-  Widget build(BuildContext context) {
-    final c = context.pangolin;
-    if (embedded) return PageBody(child: child);
-    return Scaffold(
-      backgroundColor: c.bg,
-      body: SafeArea(
-        child: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
-          Padding(
-            padding: const EdgeInsets.fromLTRB(8, 6, 16, 10),
-            child: Row(children: [
-              IconButton(
-                onPressed: onBack ?? () => Navigator.of(context).maybePop(),
-                icon: Icon(PangolinIcons.arrowLeft, size: 22, color: c.fg1),
-              ),
-              Text(title, style: PangolinText.h3.copyWith(color: c.fg1, fontWeight: FontWeight.w700)),
-            ]),
-          ),
-          Expanded(child: PageBody(child: child)),
-        ]),
-      ),
-    );
-  }
-}
-
 /// 订单页入口:内部在「列表」与「详情」两屏间切换(与原型单帧同构)。
 class OrdersScreen extends ConsumerStatefulWidget {
   const OrdersScreen({super.key, required this.t, this.onBack, this.embedded = false});
@@ -196,7 +165,7 @@ class _OrderListView extends ConsumerWidget {
           ]),
         );
 
-    return _SubScaffold(title: t.ordersTitle, onBack: onBack, embedded: embedded, child: content());
+    return SubScaffold(title: t.ordersTitle, onBack: onBack, embedded: embedded, wrapPageBody: true, child: content());
   }
 
   Widget _row(BuildContext context, PangolinScheme c, PayOrderSummary o, bool divider) {
@@ -289,7 +258,7 @@ class _OrderDetailView extends ConsumerWidget {
     final expiresAt = detailAsync.valueOrNull?.expiresAt;
     final pill = _statusPill(t, o.status);
 
-    // 内容区(mobile 套 _SubScaffold;desktop embedded 前置一条返回条回到列表)。
+    // 内容区(mobile 套 SubScaffold;desktop embedded 前置一条返回条回到列表)。
     Widget summaryCard() => Container(
           width: double.infinity,
           decoration: BoxDecoration(
@@ -376,7 +345,7 @@ class _OrderDetailView extends ConsumerWidget {
         Expanded(child: PageBody(child: body())),
       ]);
     }
-    return _SubScaffold(title: t.orderDetailTitle, onBack: onBack, child: body());
+    return SubScaffold(title: t.orderDetailTitle, onBack: onBack, wrapPageBody: true, child: body());
   }
 
   Widget _kv(PangolinScheme c, String label, String value, {VoidCallback? onCopy}) {

client/lib/screens/payment_page.dart

@@ -15,6 +15,7 @@ import '../state/payment_provider.dart';
 import '../widgets/pangolin_button.dart';
 import '../widgets/pangolin_icons.dart';
 import '../widgets/pangolin_toast.dart';
+import '../widgets/sub_scaffold.dart';
 
 class PaymentScreen extends ConsumerStatefulWidget {
   const PaymentScreen({super.key, required this.t, this.onBack, this.onDone, this.embedded = false});
@@ -311,25 +312,11 @@ class _PaymentScreenState extends ConsumerState<PaymentScreen> {
               style: PangolinText.body.copyWith(color: c.fg3))),
     };
 
-    if (embedded) return body;
-    return Scaffold(
-      backgroundColor: c.bg,
-      body: SafeArea(
-        child: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
-          Padding(
-            padding: const EdgeInsets.fromLTRB(8, 6, 16, 10),
-            child: Row(children: [
-              IconButton(
-                onPressed: onBack ?? () => Navigator.of(context).maybePop(),
-                icon: Icon(PangolinIcons.arrowLeft, size: 22, color: c.fg1),
-              ),
-              Text(t.paymentTitle,
-                  style: PangolinText.h3.copyWith(color: c.fg1, fontWeight: FontWeight.w700)),
-            ]),
-          ),
-          Expanded(child: body),
-        ]),
-      ),
+    return SubScaffold(
+      title: t.paymentTitle,
+      onBack: onBack,
+      embedded: embedded,
+      child: body,
     );
   }
 }

client/lib/screens/purchase_page.dart

@@ -11,6 +11,7 @@ import '../pangolin_theme.dart';
 import '../state/payment_provider.dart';
 import '../widgets/page_body.dart';
 import '../widgets/pangolin_icons.dart';
+import '../widgets/sub_scaffold.dart';
 import '../widgets/pangolin_toast.dart';
 import '../widgets/plan_card.dart';
 import '../widgets/seg_switch.dart';
@@ -133,25 +134,11 @@ class _PurchaseScreenState extends ConsumerState<PurchaseScreen> {
       },
     ));
 
-    if (widget.embedded) return body;
-    return Scaffold(
-      backgroundColor: c.bg,
-      body: SafeArea(
-        child: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
-          Padding(
-            padding: const EdgeInsets.fromLTRB(8, 6, 16, 10),
-            child: Row(children: [
-              IconButton(
-                onPressed: widget.onBack ?? () => Navigator.of(context).maybePop(),
-                icon: Icon(PangolinIcons.arrowLeft, size: 22, color: c.fg1),
-              ),
-              Text(t.purchaseTitle,
-                  style: PangolinText.h3.copyWith(color: c.fg1, fontWeight: FontWeight.w700)),
-            ]),
-          ),
-          Expanded(child: body),
-        ]),
-      ),
+    return SubScaffold(
+      title: t.purchaseTitle,
+      onBack: widget.onBack,
+      embedded: widget.embedded,
+      child: body,
     );
   }
 }