feat: consolidate backend and docker-compose setup

lib/core/network/api_client.dart

@@ -0,0 +1,74 @@
+import 'package:dio/dio.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+import '../../config/app_config.dart';
+
+class ApiClient {
+  late final Dio _dio;
+
+  ApiClient() {
+    _dio = Dio(
+      BaseOptions(
+        baseUrl: AppConfig.apiBaseUrl,
+        connectTimeout: const Duration(seconds: 10),
+        receiveTimeout: const Duration(minutes: 2),
+        headers: {
+          'Content-Type': 'application/json',
+          'Accept': 'application/json',
+        },
+      ),
+    );
+
+    _setupInterceptors();
+  }
+
+  void _setupInterceptors() {
+    // Request interceptor to append JWT token
+    _dio.interceptors.add(InterceptorsWrapper(
+      onRequest: (options, handler) async {
+        final prefs = await SharedPreferences.getInstance();
+        final token = prefs.getString('auth_token');
+        if (token != null) {
+          options.headers['Authorization'] = 'Bearer $token';
+        }
+        return handler.next(options);
+      },
+    ));
+
+    // Logging interceptor for debugging
+    _dio.interceptors.add(LogInterceptor(
+      requestBody: true,
+      responseBody: true,
+    ));
+
+    // Standardized Error Interceptor
+    _dio.interceptors.add(InterceptorsWrapper(
+      onError: (DioException e, handler) {
+        String errorMessage = 'An unexpected error occurred';
+        if (e.type == DioExceptionType.connectionTimeout || 
+            e.type == DioExceptionType.receiveTimeout) {
+          errorMessage = 'Connection timed out. Please try again.';
+        } else if (e.response != null) {
+          // Standardized HTTP error formatting
+          final statusCode = e.response?.statusCode;
+          errorMessage = 'Server error ($statusCode): ${e.response?.data['message'] ?? 'Unknown'}';
+        } else if (e.type == DioExceptionType.connectionError) {
+          errorMessage = 'No internet connection.';
+        }
+        
+        final customError = DioException(
+          requestOptions: e.requestOptions,
+          response: e.response,
+          type: e.type,
+          error: errorMessage,
+        );
+        return handler.next(customError);
+      },
+    ));
+
+    // Dummy Response Interceptor for Development
+    // TODO: Remove this interceptor before production release
+    // _dio.interceptors.add(DummyResponseInterceptor());
+  }
+
+  Dio get client => _dio;
+}