add refresh token

lib/features/products/presentation/pages/product_detail_page.dart

@@ -296,14 +296,18 @@ class ProductDetailPage extends ConsumerWidget {
               context,
               icon: Icons.calendar_today,
               label: 'Created',
-              value: dateFormat.format(product.createdAt),
+              value: product.createdAt != null
+                  ? dateFormat.format(product.createdAt!)
+                  : 'N/A',
             ),
             const Divider(height: 24),
             _buildInfoRow(
               context,
               icon: Icons.update,
               label: 'Last Updated',
-              value: dateFormat.format(product.updatedAt),
+              value: product.updatedAt != null
+                  ? dateFormat.format(product.updatedAt!)
+                  : 'N/A',
             ),
           ],
         ),

lib/features/products/presentation/pages/products_page.dart

@@ -493,10 +493,18 @@ class _ProductsPageState extends ConsumerState<ProductsPage> {
         sorted.sort((a, b) => b.price.compareTo(a.price));
         break;
       case ProductSortOption.newest:
-        sorted.sort((a, b) => b.createdAt.compareTo(a.createdAt));
+        sorted.sort((a, b) {
+          final aDate = a.createdAt ?? DateTime(2000);
+          final bDate = b.createdAt ?? DateTime(2000);
+          return bDate.compareTo(aDate);
+        });
         break;
       case ProductSortOption.oldest:
-        sorted.sort((a, b) => a.createdAt.compareTo(b.createdAt));
+        sorted.sort((a, b) {
+          final aDate = a.createdAt ?? DateTime(2000);
+          final bDate = b.createdAt ?? DateTime(2000);
+          return aDate.compareTo(bDate);
+        });
         break;
     }
 

lib/features/products/presentation/providers/filtered_products_provider.dart

@@ -91,10 +91,18 @@ class SortedProducts extends _$SortedProducts {
         sorted.sort((a, b) => b.price.compareTo(a.price));
         break;
       case ProductSortOption.newest:
-        sorted.sort((a, b) => b.createdAt.compareTo(a.createdAt));
+        sorted.sort((a, b) {
+          final aDate = a.createdAt ?? DateTime(2000);
+          final bDate = b.createdAt ?? DateTime(2000);
+          return bDate.compareTo(aDate);
+        });
         break;
       case ProductSortOption.oldest:
-        sorted.sort((a, b) => a.createdAt.compareTo(b.createdAt));
+        sorted.sort((a, b) {
+          final aDate = a.createdAt ?? DateTime(2000);
+          final bDate = b.createdAt ?? DateTime(2000);
+          return aDate.compareTo(bDate);
+        });
         break;
     }
 

lib/features/products/presentation/providers/filtered_products_provider.g.dart

@@ -131,7 +131,7 @@ final class SortedProductsProvider
   }
 }
 
-String _$sortedProductsHash() => r'653f1e9af8c188631dadbfe9ed7d944c6876d2d3';
+String _$sortedProductsHash() => r'8a526ae12a15ca7decc8880ebbd083df455875a8';
 
 /// Provider for sorted products
 /// Adds sorting capability on top of filtered products