const constructure

lib/infrastructure/product/datasources/local_data_provider.dart

@@ -17,7 +17,9 @@ class ProductLocalDataProvider {
   final _logName = 'ProductLocalDataProvider';
 
   final Map<String, List<ProductDto>> _queryCache = {};
-  final Duration _cacheExpiry = Duration(minutes: AppConstant.cacheExpire);
+  final Duration _cacheExpiry = const Duration(
+    minutes: AppConstant.cacheExpire,
+  );
   final Map<String, DateTime> _cacheTimestamps = {};
 
   ProductLocalDataProvider(this._databaseHelper);
@@ -281,7 +283,7 @@ class ProductLocalDataProvider {
 
       if (maps.isEmpty) {
         log('❌ Product not found: $id', name: _logName);
-        return DC.error(ProductFailure.empty());
+        return DC.error(const ProductFailure.empty());
       }
 
       final variants = await _getProductVariants(db, id);

lib/infrastructure/product/datasources/remote_data_provider.dart

@@ -41,7 +41,7 @@ class ProductRemoteDataProvider {
       );
 
       if (response.data['data'] == null) {
-        return DC.error(ProductFailure.empty());
+        return DC.error(const ProductFailure.empty());
       }
 
       final categories = ListProductDto.fromJson(