Enhance logging and error handling in getConnections callback

- Add detailed logging to track the flow and validity of user data during the getConnections event.
- Implement exception handling to manage potential access issues with user data, improving stability and error visibility.
- Ensure clear output for both successful and failed user data access attempts, aiding in debugging and monitoring.

src/websocket_server.cpp

@@ -320,10 +320,22 @@ int WebSocketServer::wsCallback(struct lws *wsi,
                         }
                     } else if (event == "getConnections") {
                         // Admin-Funktion: Liste aller aktiven Verbindungen
+                        std::cout << "[RECEIVE] getConnections: Start" << std::endl;
                         if (!ud) {
                             std::cerr << "[RECEIVE] getConnections: ud ist nullptr" << std::endl;
                             break;
                         }
+                        std::cout << "[RECEIVE] getConnections: ud ist gültig" << std::endl;
+                        
+                        // Prüfe ob ud noch gültig ist, bevor wir darauf zugreifen
+                        try {
+                            volatile bool test = ud->pongReceived;
+                            (void)test;
+                            std::cout << "[RECEIVE] getConnections: ud-Zugriff erfolgreich" << std::endl;
+                        } catch (...) {
+                            std::cerr << "[RECEIVE] getConnections: ud ist ungültig (Exception beim Zugriff)" << std::endl;
+                            break;
+                        }
                         
                         if (ud->userId.empty()) {
                             std::cerr << "[RECEIVE] getConnections: User-ID nicht gesetzt" << std::endl;