Scaffold Block Seasons Flutter app

flutter create (com.airkjw.blockseasons, iOS+Android), Riverpod,
shared_preferences, audioplayers, gen-l10n EN/KO wiring, app shell
with Home -> Game placeholder.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

lib/main.dart

@@ -0,0 +1,9 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+import 'app.dart';
+
+void main() {
+  WidgetsFlutterBinding.ensureInitialized();
+  runApp(const ProviderScope(child: BlockSeasonsApp()));
+}