Upgrade heatmaps stile Hotjar: movimenti mouse e anteprima pagina live.

Traccia i movimenti aggregati, overlay a gradienti sull’iframe della pagina e toggle click/move in admin.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/app/views/layouts/marketing_live.html.erb

@@ -21,7 +21,7 @@
     <%= render "shared/marketing_footer" %>
     <link rel="stylesheet" href="/confirm-forms.css?v=4">
     <script src="/confirm-forms.js?v=7" defer></script>
-    <script src="/site-analytics.js?v=1" defer></script>
+    <script src="/site-analytics.js?v=2" defer></script>
     <script src="/cookie-consent.js?v=2" defer></script>
   </body>
 </html>