completed migrating data scope from user to workspace

lib/screens/workspaces/workspace_provider.dart

@@ -0,0 +1,73 @@
+import 'package:flutter/foundation.dart';
+import 'package:qpay/http/http.dart';
+import 'package:qpay/screens/workspaces/workspace_model.dart';
+
+/// Describes the current state of the workspace fetch operation.
+enum WorkspaceStatus { idle, loading, success, error }
+
+/// A [ChangeNotifier] that fetches and caches the list of workspaces
+/// for the current user from the backend.
+///
+/// Usage:
+/// ```dart
+/// final provider = context.read<WorkspaceProvider>();
+/// await provider.fetchWorkspaces(userId: '...');
+/// ```
+class WorkspaceProvider extends ChangeNotifier {
+  final Http _http = Http();
+
+  WorkspaceStatus _status = WorkspaceStatus.idle;
+  List<WorkspaceModel> _workspaces = [];
+  String? _error;
+
+  WorkspaceStatus get status => _status;
+  List<WorkspaceModel> get workspaces => _workspaces;
+  String? get error => _error;
+  bool get isLoading => _status == WorkspaceStatus.loading;
+  bool get hasError => _status == WorkspaceStatus.error;
+
+  /// Fetches workspaces for the given [userId].
+  ///
+  /// On success, [workspaces] is updated and [status] becomes
+  /// [WorkspaceStatus.success].
+  /// On failure, [error] is set and [status] becomes
+  /// [WorkspaceStatus.error].
+  Future<void> fetchWorkspaces({required String userId}) async {
+    _status = WorkspaceStatus.loading;
+    _error = null;
+    notifyListeners();
+
+    try {
+      final response = await _http.getRaw('/workspaces?userId=$userId');
+
+      if (response.statusCode == 200) {
+        final body = response.data as Map<String, dynamic>;
+        final content = body['content'] as List<dynamic>;
+        _workspaces = content
+            .map((e) => WorkspaceModel.fromJson(e as Map<String, dynamic>))
+            .toList();
+        _status = WorkspaceStatus.success;
+      } else if (response.statusCode == 403) {
+        _error =
+            'Access denied. You do not have permission to view workspaces.';
+        _status = WorkspaceStatus.error;
+      } else {
+        _error = 'Failed to load workspaces (status ${response.statusCode})';
+        _status = WorkspaceStatus.error;
+      }
+    } catch (e) {
+      _error = 'Network error: ${e.toString()}';
+      _status = WorkspaceStatus.error;
+    }
+
+    notifyListeners();
+  }
+
+  /// Clears the current workspace list and resets to idle.
+  void reset() {
+    _status = WorkspaceStatus.idle;
+    _workspaces = [];
+    _error = null;
+    notifyListeners();
+  }
+}