Initialize project and update portal port configuration

Set default portal port to 8081, fix Dart build issue in cart screen, and update setup documentation.

Co-Authored-By: Oz <oz-agent@warp.dev>

lib/services/app_config_service.dart

@@ -0,0 +1,47 @@
+import 'dart:convert';
+
+import 'package:firebase_core/firebase_core.dart';
+import 'package:flutter/services.dart';
+
+class AppConfigService {
+  AppConfigService._();
+
+  static final AppConfigService instance = AppConfigService._();
+
+  bool _initialized = false;
+
+  Future<void> initialize() async {
+    if (_initialized) return;
+
+    final configRaw =
+        await rootBundle.loadString('assets/config/runtime_config.json');
+    final Map<String, dynamic> config = json.decode(configRaw);
+
+    await Firebase.initializeApp(
+      options: FirebaseOptions(
+        apiKey: _required(config, 'firebase_api_key'),
+        appId: _required(config, 'firebase_app_id'),
+        messagingSenderId: _required(config, 'firebase_messaging_sender_id'),
+        projectId: _required(config, 'firebase_project_id'),
+        authDomain: _required(config, 'firebase_auth_domain'),
+        storageBucket: _required(config, 'firebase_storage_bucket'),
+        measurementId: _optional(config, 'firebase_measurement_id'),
+      ),
+    );
+
+    _initialized = true;
+  }
+
+  String _required(Map<String, dynamic> config, String key) {
+    final value = (config[key] ?? '').toString().trim();
+    if (value.isEmpty || value.startsWith('replace-with-')) {
+      throw StateError('Missing required runtime configuration: $key');
+    }
+    return value;
+  }
+
+  String? _optional(Map<String, dynamic> config, String key) {
+    final value = (config[key] ?? '').toString().trim();
+    return value.isEmpty ? null : value;
+  }
+}

lib/services/auth_service.dart

@@ -0,0 +1,48 @@
+import 'package:firebase_auth/firebase_auth.dart';
+
+class AuthService {
+  AuthService._();
+
+  static final AuthService instance = AuthService._();
+  final FirebaseAuth _auth = FirebaseAuth.instance;
+
+  Stream<User?> authStateChanges() => _auth.authStateChanges();
+
+  User? get currentUser => _auth.currentUser;
+
+  Future<UserCredential> signInWithEmailPassword({
+    required String email,
+    required String password,
+  }) {
+    return _auth.signInWithEmailAndPassword(email: email, password: password);
+  }
+
+  Future<UserCredential> registerWithEmailPassword({
+    required String email,
+    required String password,
+  }) {
+    return _auth.createUserWithEmailAndPassword(
+      email: email,
+      password: password,
+    );
+  }
+
+  Future<void> sendPasswordResetEmail(String email) {
+    return _auth.sendPasswordResetEmail(email: email);
+  }
+
+  Future<UserCredential> signInWithGoogle() {
+    final provider = GoogleAuthProvider();
+    provider.setCustomParameters({'prompt': 'select_account'});
+    return _auth.signInWithPopup(provider);
+  }
+
+  Future<UserCredential> signInWithGithub() {
+    final provider = GithubAuthProvider();
+    return _auth.signInWithPopup(provider);
+  }
+
+  Future<void> signOut() {
+    return _auth.signOut();
+  }
+}

lib/services/cart_service.dart

@@ -0,0 +1,43 @@
+import 'package:flutter/foundation.dart';
+
+import '../models/cart_item.dart';
+import '../models/product.dart';
+
+class CartService extends ChangeNotifier {
+  final List<CartItem> _items = [];
+
+  List<CartItem> get items => List.unmodifiable(_items);
+
+  int get totalItems => _items.fold(0, (sum, item) => sum + item.quantity);
+
+  double get totalPrice =>
+      _items.fold(0.0, (sum, item) => sum + item.lineTotal);
+
+  void addProduct(Product product) {
+    final index = _items.indexWhere((item) => item.product.id == product.id);
+    if (index == -1) {
+      _items.add(CartItem(product: product));
+    } else {
+      _items[index].quantity += 1;
+    }
+    notifyListeners();
+  }
+
+  void removeProduct(String productId) {
+    _items.removeWhere((item) => item.product.id == productId);
+    notifyListeners();
+  }
+
+  void updateQuantity(String productId, int quantity) {
+    if (quantity < 1) return;
+    final index = _items.indexWhere((item) => item.product.id == productId);
+    if (index == -1) return;
+    _items[index].quantity = quantity;
+    notifyListeners();
+  }
+
+  void clear() {
+    _items.clear();
+    notifyListeners();
+  }
+}

lib/services/product_repository.dart

@@ -0,0 +1,55 @@
+import '../models/product.dart';
+
+class ProductRepository {
+  static const List<Product> products = [
+    Product(
+      id: 'p1',
+      name: 'Minimalist Chair',
+      description: 'Ergonomic chair with breathable fabric and oak finish.',
+      imageUrl: 'https://picsum.photos/seed/chair/900/600',
+      price: 129.99,
+    ),
+    Product(
+      id: 'p2',
+      name: 'Modern Table Lamp',
+      description: 'Warm ambient lighting with dimmable touch controls.',
+      imageUrl: 'https://picsum.photos/seed/lamp/900/600',
+      price: 59.50,
+    ),
+    Product(
+      id: 'p3',
+      name: 'Noise-Cancel Headphones',
+      description: 'Wireless over-ear headphones with premium audio.',
+      imageUrl: 'https://picsum.photos/seed/headphones/900/600',
+      price: 219.00,
+    ),
+    Product(
+      id: 'p4',
+      name: 'Smart Watch',
+      description: 'Fitness tracking, sleep monitoring, and message alerts.',
+      imageUrl: 'https://picsum.photos/seed/watch/900/600',
+      price: 179.90,
+    ),
+    Product(
+      id: 'p5',
+      name: 'Travel Backpack',
+      description: 'Water-resistant backpack with dedicated laptop sleeve.',
+      imageUrl: 'https://picsum.photos/seed/backpack/900/600',
+      price: 89.00,
+    ),
+    Product(
+      id: 'p6',
+      name: 'Mechanical Keyboard',
+      description: 'Hot-swappable switches and customizable RGB lighting.',
+      imageUrl: 'https://picsum.photos/seed/keyboard/900/600',
+      price: 149.00,
+    ),
+  ];
+
+  static Product? byId(String id) {
+    for (final product in products) {
+      if (product.id == id) return product;
+    }
+    return null;
+  }
+}