qt: titlebar should be visible by default

CSD where active by default, even when the feature wasn't available

fix: #26293

modules/gui/qt/maininterface/main_interface.hpp

@@ -281,7 +281,7 @@ protected:
     MediaLib*            m_medialib = nullptr;
     bool                 m_gridView = false;
     ColorSchemeModel*    m_colorScheme = nullptr;
-    bool                 m_windowTitlebar = false;
+    bool                 m_windowTitlebar = true;
     bool                 m_hasToolbarMenu = false;
     bool                 m_canShowVideoPIP = false;
     bool                 m_pinVideoControls = false;