fix: coklu monitorde cascade dogru ekrani kullanir, .deb guncellendi

- window_persistence: onceki pencerenin bulundugu monitorun calisma alani kullanilir (getAllDisplays), primary degil
- viewer_screen: catchError donus tipi duzeltildi (analyze warning)
- dist/imajviewer_1.0.0_amd64.deb yeniden derlendi

lib/screens/viewer_screen.dart

@@ -60,7 +60,7 @@ class _ViewerScreenState extends State<ViewerScreen> with WindowListener {
       case 'resize':
       case 'move':
         // Son bilinen konumu hemen güncelle (kapanış senkron kaydı için)
-        windowManager.getBounds().then((b) => _lastBounds = b).catchError((_) {});
+        windowManager.getBounds().then((b) => _lastBounds = b).catchError((_) => _lastBounds);
         _saveDebounce?.cancel();
         _saveDebounce = Timer(const Duration(milliseconds: 300), () {
           _doSave();