fix: defer startPolling until all NVD3 charts initialized

nv.addGraph uses setTimeout internally, so chart models may not exist yet
when the first WebSocket response arrives. Moved startPolling() into the
last nv.addGraph callback to guarantee charts are ready before data flows.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

js/pages/serverInfo.js

@@ -99,6 +99,10 @@ function ServerInfoPage(params, container) {
     d3.select('#chart-players').datum([]).call(playersChart);
 
     window._playersChart = playersChart;
+
+    // All charts ready — start polling data
+    if (Rcon.isConnected()) startPolling();
+    else { var _c = function () { startPolling(); Rcon.off('connected', _c); }; Rcon.on('connected', _c); }
   });
 
   // ---- Data polling ----
@@ -183,9 +187,6 @@ function ServerInfoPage(params, container) {
     pollTimer = setInterval(refresh, 1000);
   }
 
-  if (Rcon.isConnected()) startPolling();
-  else { var _c = function () { startPolling(); Rcon.off('connected', _c); }; Rcon.on('connected', _c); }
-
   return function cleanup() {
     if (pollTimer) clearInterval(pollTimer);
     window._perfChart = null;