fix: call AiLab.init() on DOMContentLoaded so batch sim panel renders

The ai-lab.js IIFE defines the AiLab global with an init() method that
calls renderPanel(), detectBackend(), loadAvailableDecks(),
loadMetaCommanders(), loadPrecons(), and bindEvents() — but nothing
ever invoked it. Added a DOMContentLoaded listener after the script tag
in index.html to trigger initialization.

ui/index.html

@@ -197,5 +197,6 @@
     </div>
 
     <script src="ai-lab.js"></script>
+    <script>document.addEventListener('DOMContentLoaded', () => AiLab.init());</script>
 </body>
 </html>