design+client: 抽 .view-body/PageBody 统一桌面内容页宽度(600/wide 840)——stats·contact 补约束,settings·contact 560→600,九页收口

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01P9G7E3wmAYL9KeYCVZVsqu

client/lib/screens/settings_page.dart

@@ -13,6 +13,7 @@ import '../services/web_launch.dart';
 import '../state/app_providers.dart';
 import '../state/settings_provider.dart';
 import '../state/update_provider.dart';
+import '../widgets/page_body.dart';
 import '../widgets/pangolin_icons.dart';
 import '../widgets/pangolin_toast.dart';
 
@@ -54,8 +55,7 @@ class SettingsPage extends ConsumerWidget {
 
     return SingleChildScrollView(
       padding: const EdgeInsets.fromLTRB(32, 16, 32, 24),
-      child: ConstrainedBox(
-        constraints: const BoxConstraints(maxWidth: 560),
+      child: PageBody(
         child: Column(crossAxisAlignment: CrossAxisAlignment.stretch, children: [
           // ① 连接（功能开关组；开机自启是桌面端登录项概念,iOS/Android 无此能力,仅桌面显示）
           _SectionLabel(text: t.settingsGroupConn),