refactor: introduce base API service and core service for standardized API interaction and error handling.

apps/mobile/packages/domain/lib/krow_domain.dart

@@ -7,7 +7,9 @@
 library;
 
 // Core
-export 'src/entities/core/services/api_service/api_response.dart';
+export 'src/core/services/api_services/api_response.dart';
+export 'src/core/services/api_services/base_api_service.dart';
+export 'src/core/services/api_services/base_core_service.dart';
 
 // Users & Membership
 export 'src/entities/users/user.dart';

apps/mobile/packages/domain/lib/src/core/services/api_services/api_response.dart

@@ -18,5 +18,5 @@ class ApiResponse {
   final dynamic data;
 
   /// A map of field-specific error messages, if any.
-  final Map<String, dynamic?> errors;
+  final Map<String, dynamic> errors;
 }

apps/mobile/packages/domain/lib/src/core/services/api_services/base_api_service.dart

@@ -0,0 +1,30 @@
+import 'api_response.dart';
+
+/// Abstract base class for API services.
+///
+/// This defines the contract for making HTTP requests.
+abstract class BaseApiService {
+  /// Performs a GET request to the specified [endpoint].
+  Future<ApiResponse> get(String endpoint, {Map<String, dynamic>? params});
+
+  /// Performs a POST request to the specified [endpoint].
+  Future<ApiResponse> post(
+    String endpoint, {
+    dynamic data,
+    Map<String, dynamic>? params,
+  });
+
+  /// Performs a PUT request to the specified [endpoint].
+  Future<ApiResponse> put(
+    String endpoint, {
+    dynamic data,
+    Map<String, dynamic>? params,
+  });
+
+  /// Performs a PATCH request to the specified [endpoint].
+  Future<ApiResponse> patch(
+    String endpoint, {
+    dynamic data,
+    Map<String, dynamic>? params,
+  });
+}

apps/mobile/packages/domain/lib/src/core/services/api_services/base_core_service.dart

@@ -0,0 +1,29 @@
+import 'api_response.dart';
+import 'base_api_service.dart';
+
+/// Abstract base class for core business services.
+///
+/// This provides a common [action] wrapper for standardized execution
+/// and error catching across all core service implementations.
+abstract class BaseCoreService {
+  /// Creates a [BaseCoreService] with the given [api] client.
+  const BaseCoreService(this.api);
+
+  /// The API client used to perform requests.
+  final BaseApiService api;
+
+  /// Standardized wrapper to execute API actions.
+  ///
+  /// This handles generic error normalization for unexpected non-HTTP errors.
+  Future<ApiResponse> action(Future<ApiResponse> Function() execution) async {
+    try {
+      return await execution();
+    } catch (e) {
+      return ApiResponse(
+        code: 'CORE_INTERNAL_ERROR',
+        message: e.toString(),
+        errors: <String, dynamic>{'exception': e.runtimeType.toString()},
+      );
+    }
+  }
+}