add refresh token

lib/features/categories/data/models/category_model.dart

@@ -25,10 +25,10 @@ class CategoryModel extends HiveObject {
   final int productCount;
 
   @HiveField(6)
-  final DateTime createdAt;
+  final DateTime? createdAt;
 
   @HiveField(7)
-  final DateTime updatedAt;
+  final DateTime? updatedAt;
 
   CategoryModel({
     required this.id,
@@ -37,8 +37,8 @@ class CategoryModel extends HiveObject {
     this.iconPath,
     this.color,
     required this.productCount,
-    required this.createdAt,
-    required this.updatedAt,
+    this.createdAt,
+    this.updatedAt,
   });
 
   /// Convert to domain entity
@@ -78,8 +78,12 @@ class CategoryModel extends HiveObject {
       iconPath: json['iconPath'] as String?,
       color: json['color'] as String?,
       productCount: json['productCount'] as int? ?? 0,
-      createdAt: DateTime.parse(json['createdAt'] as String),
-      updatedAt: DateTime.parse(json['updatedAt'] as String),
+      createdAt: json['createdAt'] != null
+          ? DateTime.parse(json['createdAt'] as String)
+          : null,
+      updatedAt: json['updatedAt'] != null
+          ? DateTime.parse(json['updatedAt'] as String)
+          : null,
     );
   }
 
@@ -92,8 +96,8 @@ class CategoryModel extends HiveObject {
       'iconPath': iconPath,
       'color': color,
       'productCount': productCount,
-      'createdAt': createdAt.toIso8601String(),
-      'updatedAt': updatedAt.toIso8601String(),
+      'createdAt': createdAt?.toIso8601String(),
+      'updatedAt': updatedAt?.toIso8601String(),
     };
   }
 

lib/features/categories/data/models/category_model.g.dart

@@ -23,8 +23,8 @@ class CategoryModelAdapter extends TypeAdapter<CategoryModel> {
       iconPath: fields[3] as String?,
       color: fields[4] as String?,
       productCount: (fields[5] as num).toInt(),
-      createdAt: fields[6] as DateTime,
-      updatedAt: fields[7] as DateTime,
+      createdAt: fields[6] as DateTime?,
+      updatedAt: fields[7] as DateTime?,
     );
   }
 

lib/features/categories/domain/entities/category.dart

@@ -8,8 +8,8 @@ class Category extends Equatable {
   final String? iconPath;
   final String? color;
   final int productCount;
-  final DateTime createdAt;
-  final DateTime updatedAt;
+  final DateTime? createdAt;
+  final DateTime? updatedAt;
 
   const Category({
     required this.id,
@@ -18,8 +18,8 @@ class Category extends Equatable {
     this.iconPath,
     this.color,
     required this.productCount,
-    required this.createdAt,
-    required this.updatedAt,
+    this.createdAt,
+    this.updatedAt,
   });
 
   @override