feat(dependencies): add rxdart package and improve string extension methods for better handling of empty strings and gender parsing

test/features/chat/models/chat_user_model_test.dart

@@ -0,0 +1,32 @@
+import 'package:eatvio_app/features/chat/models/chat_user_model.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  group('ChatUserModel', () {
+    test('создает ChatUserModel с правильными значениями', () {
+      const model = ChatUserModel(
+        id: 1,
+        name: 'User Name',
+        slug: 'user-slug',
+        profilePhotoUrl: 'https://example.com/photo.jpg',
+      );
+
+      expect(model.id, 1);
+      expect(model.name, 'User Name');
+      expect(model.slug, 'user-slug');
+      expect(model.profilePhotoUrl, 'https://example.com/photo.jpg');
+    });
+
+    test('создает ChatUserModel без фото', () {
+      const model = ChatUserModel(
+        id: 1,
+        name: 'User Name',
+        slug: 'user-slug',
+        profilePhotoUrl: null,
+      );
+
+      expect(model.profilePhotoUrl, isNull);
+    });
+  });
+}
+