lib/
├── core/
│   ├── theme/
│   └── widgets/
├── features/
│   ├── auth/
│   │   ├── data/
│   │   ├── domain/
│   │   └── presentation/
│   └── home/
├── services/
└── main.dart

// ✅ const constructor kullan
class MyButton extends StatelessWidget {
  const MyButton({super.key, required this.onPressed});
  final VoidCallback onPressed;

  @override
  Widget build(BuildContext context) {
    return ElevatedButton(onPressed: onPressed, child: Text('Click'));
  }
}

// ✅ const widget'ları işaretle
const SizedBox(height: 16),

final authProvider = StateNotifierProvider<AuthNotifier, AuthState>((ref) {
  return AuthNotifier(ref.watch(authRepositoryProvider));
});

class AuthNotifier extends StateNotifier<AuthState> {
  AuthNotifier(this._repo) : super(const AuthState());
  
  Future<void> login(String email, String password) async {
    state = state.copyWith(isLoading: true);
    final user = await _repo.login(email, password);
    state = state.copyWith(user: user, isLoading: false);
  }
}

// ✅ ListView.builder (lazy loading)
ListView.builder(
  itemCount: items.length,
  itemBuilder: (context, index) => ItemCard(item: items[index]),
)

// ✅ RepaintBoundary
RepaintBoundary(child: ExpensiveWidget())

// ✅ Isolate for CPU-heavy
final result = await compute(parseUsers, jsonString);

import 'package:flutter_secure_storage/flutter_secure_storage.dart';

final storage = FlutterSecureStorage();
await storage.write(key: 'token', value: token);
final token = await storage.read(key: 'token');

// MediaQuery
final isTablet = MediaQuery.of(context).size.width > 600;

// LayoutBuilder
LayoutBuilder(
  builder: (context, constraints) {
    return constraints.maxWidth > 600 ? WideLayout() : NarrowLayout();
  },
)