Fix re-declaration of poll timer causing UX to fail

web/templates/index.html

@@ -732,7 +732,7 @@ function clearForm() {
 
 let lastAppliedVersion = -1;
 let lastServerInstance = null;
-let pollTimer          = null;
+// pollTimer is declared once in the State block near the top of this script.
 
 /**
  * Apply a server snapshot to the DOM, but only if it's strictly newer than
@@ -920,4 +920,4 @@ function cssEsc(s) {
 }
 </script>
 </body>
-</html>
+</html>