간편 로그인 · 성운/행성 생성을 아래에서 올라오는 전환으로

app/lib/features/auth/onboarding_screens.dart

@@ -5,6 +5,7 @@ import '../../core/i18n/app_locale.dart';
 import '../../core/push/push_messaging.dart';
 import '../../core/theme/tokens.dart';
 import '../../core/ui/app_icons.dart';
+import '../../core/ui/sheet_route.dart';
 import '../home/coach_mark.dart';
 import '../home/home_data.dart';
 import '../home/nebula_create_screen.dart';
@@ -259,7 +260,7 @@ class _OnboardingFlowState extends State<OnboardingFlow> {
         }),
         onCreateNebula: () async {
           final created = await Navigator.of(context).push<String>(
-            MaterialPageRoute(
+            SheetRoute(
               builder: (_) => NebulaCreateScreen(repository: widget.home),
             ),
           );