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

src/Entity/LogEntry.php

@@ -112,6 +112,11 @@ class LogEntry
         return $this->getExtra()['request_id'] ?? '-';
     }
 
+    public function getErrorCode(): string
+    {
+        return $this->getExtra()['error_code'] ?? '-';
+    }
+
     public function getUri(): string
     {
         return $this->getExtra()['uri'] ?? '';