feat(frontend): make baseUrl dynamic for external network access and clear default login inputs

FinlyticApp/lib/core/network/api_client.dart

@@ -1,4 +1,5 @@
 import 'package:dio/dio.dart';
+import 'package:flutter/foundation.dart';
 import '../services/secure_storage_service.dart';
 
 /// Central HTTP ApiClient backed by Dio with automatic 401 Unauthorized handling.
@@ -7,7 +8,15 @@ class ApiClient {
   late final Dio _dio;
   Function()? onUnauthorized;
 
-  static const String baseUrl = 'http://localhost:5000';
+  static String get baseUrl {
+    if (kIsWeb) {
+      final origin = Uri.base.origin;
+      if (origin.isNotEmpty && !origin.contains('null') && !origin.startsWith('file:')) {
+        return origin;
+      }
+    }
+    return const String.fromEnvironment('BACKEND_URL', defaultValue: 'http://localhost:5000');
+  }
 
   ApiClient(this._storageService) {
     _dio = Dio(

FinlyticApp/lib/core/network/signalr_service.dart

@@ -1,4 +1,5 @@
 import 'dart:async';
+import 'package:finlytic_app/core/network/api_client.dart';
 import 'package:flutter/foundation.dart';
 import 'package:signalr_core/signalr_core.dart';
 import '../services/secure_storage_service.dart';
@@ -21,7 +22,7 @@ class SignalRService extends ChangeNotifier {
   Stream<List<Map<String, dynamic>>> get healthStream => _healthController.stream;
   Stream<Map<String, dynamic>> get favoritePricesStream => _favoritePricesController.stream;
 
-  static const String baseUrl = 'http://localhost:5000';
+  static String get baseUrl => ApiClient.baseUrl;
 
   SignalRService(this.storageService);
 

FinlyticApp/lib/features/auth/views/login_screen.dart

@@ -14,8 +14,15 @@ class LoginScreen extends StatefulWidget {
 
 class _LoginScreenState extends State<LoginScreen> {
   final _formKey = GlobalKey<FormState>();
-  final _emailController = TextEditingController(text: 'admin@finlytic.com');
-  final _passwordController = TextEditingController(text: 'AdminDefaultPassword2026!');
+  final _emailController = TextEditingController();
+  final _passwordController = TextEditingController();
+
+  @override
+  void dispose() {
+    _emailController.dispose();
+    _passwordController.dispose();
+    super.dispose();
+  }
 
   void _onLogin() {
     if (_formKey.currentState?.validate() ?? false) {

FinlyticApp/lib/features/dashboard/widgets/daily_news_snapshot.dart

@@ -14,19 +14,19 @@ import '../../news/widgets/article_sentiment_dialog.dart';
 
 class DailyNewsSnapshot extends StatelessWidget {
   final ApiClient apiClient;
-  final String backendUrl;
+  final String? backendUrl;
 
   const DailyNewsSnapshot({
     super.key,
     required this.apiClient,
-    this.backendUrl = 'http://localhost:5000',
+    this.backendUrl,
   });
 
   @override
   Widget build(BuildContext context) {
     return BlocProvider(
       create: (context) => NewsBloc(
-        repository: NewsRepository(apiClient: apiClient, backendUrl: backendUrl),
+        repository: NewsRepository(apiClient: apiClient, backendUrl: backendUrl ?? ApiClient.baseUrl),
       )..add(FetchNews(date: DateTime.now().toIso8601String().substring(0, 10))),
       child: const _DailyNewsSnapshotContent(),
     );