feat(flutter): 统一二级页头并恢复新剧暖色

lib/pages/mine/mine_view.dart

@@ -14,6 +14,7 @@ import '../../core/theme/app_dimens.dart';
 import '../../core/theme/app_theme.dart';
 import '../../core/widgets/app_bottom_nav.dart';
 import '../../core/widgets/auth_gate.dart';
+import '../../core/widgets/plain_page_scaffold.dart';
 import '../../l10n/app_localizations.dart';
 import '../downloads/downloads_page.dart';
 import '../favorites/favorites_page.dart';
@@ -364,11 +365,11 @@ class _MinePlaceholderPage extends StatelessWidget {
       MinePlaceholderKind.creator => l10n.creatorCenter,
       MinePlaceholderKind.help => l10n.helpFeedback,
     };
-    return Scaffold(
-      key: const Key('mine-placeholder-page'),
-      backgroundColor: AppColors.ink,
-      appBar: AppBar(title: Text(title)),
-      body: Center(
+    return PlainPageScaffold(
+      pageKey: const Key('mine-placeholder-page'),
+      backKey: const Key('mine-placeholder-back'),
+      title: title,
+      child: Center(
         child: Text(
           l10n.comingSoon,
           style: const TextStyle(