fix: Window shows in taskbar

Added Qt.Window flag to ensure window appears in Windows taskbar
so user can close it from taskbar.

projects/EU-Utility/core/overlay_window.py

@@ -52,11 +52,12 @@ class OverlayWindow(QMainWindow):
         self.hide_overlay()
     
     def _setup_window(self):
-        """Configure window - resizable and shows in taskbar."""
+        """Configure window - resizable, shows in taskbar."""
         self.setWindowTitle("EU-Utility")
         
-        # Resizable window, stays on top
+        # Resizable window, stays on top, shows in taskbar
         self.setWindowFlags(
+            Qt.WindowType.Window |
             Qt.WindowType.WindowStaysOnTopHint
         )