feat: implement type-safe ReferenceProperty for SmartPointer fields and add UI support for object selection via context-aware dropdowns

app/gcompose/src/PropertyWidgets.cpp

@@ -425,7 +425,6 @@ void ReferencePropertyWidget::refreshCombo() {
     Object* currentRef = m_RefProp->GetReferencedObject();
 
     if (m_Context) {
-        const auto& objects = m_Context->GetObjects();
         for (const auto& obj : objects) {
             if (m_RefProp->IsCompatible(obj.get())) {
                 QString label = QString::fromStdString(obj->GetInstanceName());