fix logosAPI variable handling

tutorial-cpp-ui-app.md

@@ -244,7 +244,6 @@ signals:
     void eventResponse(const QString& eventName, const QVariantList& args);
 
 private:
-    LogosAPI* m_logosAPI = nullptr;
     LogosModules* m_logos = nullptr;
 };
 ```
@@ -269,7 +268,9 @@ CalcUiCppPlugin::~CalcUiCppPlugin() { delete m_logos; }
 
 void CalcUiCppPlugin::initLogos(LogosAPI* api)
 {
-    m_logosAPI = api;
+    // Assign to the inherited `logosAPI` member from PluginInterface — the Logos
+    // host reads it directly to dispatch calls; a separate member won't be seen.
+    logosAPI = api;
     m_logos = new LogosModules(api);
     // Register this object as the Remote Objects source
     setBackend(this);