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

app/gcompose/src/PropertiesPanel.h

@@ -24,6 +24,9 @@ public:
     /** @brief Sets the object to be inspected. */
     void setObject(uLib::Object* obj);
 
+signals:
+    void propertyUpdated();
+
 private:
     QVBoxLayout* m_layout;
     QWidget* m_titleBar;