ui: add a useless service worker

packages/ui-default/entry.js

@@ -27,6 +27,16 @@ console.log(
 `,
 );
 
+if ('serviceWorker' in navigator) {
+  window.addEventListener('load', () => {
+    navigator.serviceWorker.register(new URL('./service-worker', import.meta.url)).then((registration) => {
+      console.log('SW registered: ', registration);
+    }).catch((registrationError) => {
+      console.log('SW registration failed: ', registrationError);
+    });
+  });
+}
+
 document.addEventListener('DOMContentLoaded', async () => {
   window.UiContext = JSON.parse(window.UiContext);