WIP: Tell Puter to run us as a headless app

This is likely to change depending on how that API ends up.

assets/index.html

@@ -12,6 +12,8 @@
     <script src="config.js"></script>
     <script src="bundle.js"></script>
     <script>
+        puter.ui.configureWindow({ headless: true });
+
         document.addEventListener('DOMContentLoaded', async () => {
             main_shell();
         });