fix: title bar inceltildi (28px), degrade kaldırıldı

lib/screens/viewer_screen.dart

@@ -119,7 +119,7 @@ class _ViewerScreenState extends State<ViewerScreen> with WindowListener {
             child: Stack(
               children: [
                 Positioned(
-                  top: 40,
+                  top: 28,
                   left: 0,
                   right: 0,
                   bottom: 0,