fix: add loading indicators to all pages

- 'Loading…' shown in charts/fields/output areas while waiting for server response
- Console + chat: clears loading state on first output line
- Player list: table body shows loading row until refresh completes
- Player info / Server info: fields show loading until data arrives

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

js/pages/serverInfo.js

@@ -9,7 +9,7 @@ function ServerInfoPage(params, container) {
     '<div id="ServerInfoController">' +
       '<div class="row">' +
         '<div class="col-sm-12"><h2 id="si-hostname">Server Info</h2></div>' +
-        '<div id="si-fields" class="col-sm-12"></div>' +
+        '<div id="si-fields" class="col-sm-12"><span class="text-white-50">Loading…</span></div>' +
       '</div>' +
       '<div class="row">' +
         '<div class="col-sm-12">' +