feat: implement configurable font settings for VTK viewports and GUI elements with persistent preferences.

app/gcompose/src/ContextPanel.h

@@ -25,6 +25,7 @@ public:
 
 signals:
     void objectSelected(uLib::Object* obj);
+    void propertyUpdated();
 
 private slots:
     void onSelectionChanged(const QItemSelection& selected, const QItemSelection& deselected);