Fix stale UI cache with network-first app shell and forced SW updates

app/public/index.html

@@ -297,7 +297,18 @@
 <script src="app.js"></script>
 <script>
   if ('serviceWorker' in navigator) {
-    navigator.serviceWorker.register('/sw.js');
+    window.addEventListener('load', () => {
+      navigator.serviceWorker.register('/sw.js').then(reg => {
+        reg.update().catch(() => {});
+      });
+
+      let refreshing = false;
+      navigator.serviceWorker.addEventListener('controllerchange', () => {
+        if (refreshing) return;
+        refreshing = true;
+        window.location.reload();
+      });
+    });
   }
 </script>
 </body>