feat: Update API endpoint usage in repositories to remove redundant path property

- Refactored multiple repository implementations across client and staff features to directly use endpoint objects without accessing the `path` property.
- Introduced a new `FeatureGate` class for client-side feature gating based on user scopes, allowing for better access control to API endpoints.
- Added `ApiEndpoint` class to represent API endpoints with their paths and required scopes for future feature gating.

apps/mobile/packages/features/staff/staff_main/lib/src/data/repositories/staff_main_repository_impl.dart

@@ -23,7 +23,7 @@ class StaffMainRepositoryImpl implements StaffMainRepositoryInterface {
   Future<bool> getProfileCompletion() async {
     try {
       final ApiResponse response = await _apiService.get(
-        StaffEndpoints.profileCompletion.path,
+        StaffEndpoints.profileCompletion,
       );
 
       if (response.data is Map<String, dynamic>) {