Improve error reporting

src/main/resources/templates/admin.html

@@ -208,6 +208,7 @@
 <script th:inline="javascript">
     const broadcaster = /*[[${broadcaster}]]*/ '';
     const username = /*[[${username}]]*/ '';
+    const upload_limit_bytes = /*[[${uploadLimitBytes}]]*/ + 0;
 </script>
 <script src="/js/toast.js"></script>
 <script src="/js/admin.js"></script>