feat: error-codes in flash messages to reference log entries

templates/_partials/_alert.html.twig

@@ -35,6 +35,11 @@
                     </ul>
                 </div>
             {% endif %}
+            {% if level == 'error' and has_error_code() %}
+                <div class="pt-8 text-white text-sm font-mono">
+                    Fehlercode (bitte angeben): {{ error_code() }}
+                </div>
+            {% endif %}
         </div>
     </div>
 </div>