Initial commit: Grav CMS setup with HTML reference material

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

plugins/form/app/utils/keep-alive.js

@@ -0,0 +1,17 @@
+import $ from 'jquery';
+import {config} from 'grav-form';
+
+const MAX_SAFE_DELAY = 2147483647;
+
+$(document).ready(() => {
+    const keepAlive = $('[data-grav-keepalive]');
+
+    if (keepAlive.length) {
+        const timeout = config.session_timeout / 1.5 * 1000;
+        setInterval(() => {
+            $.ajax({
+                url: `${config.base_url_relative}/task${config.param_sep}keep-alive`
+            });
+        }, Math.min(timeout, MAX_SAFE_DELAY));
+    }
+});