fix(gateway-ui): refresh service worker and static cache headers

src/gateway/ui/lib/pwa.js

@@ -60,7 +60,10 @@ export async function registerPwaServiceWorker() {
   if (!('serviceWorker' in navigator)) {
     return null;
   }
-  return navigator.serviceWorker.register(withToken('/sw.js'));
+  const registration = await navigator.serviceWorker.register(withToken('/sw.js'));
+  // Ask the browser to check for a newer worker on app load.
+  void registration.update().catch(() => undefined);
+  return registration;
 }
 
 export async function getPushStatus() {

src/gateway/ui/sw.js

@@ -1,4 +1,4 @@
-const CACHE_NAME = 'flynn-webchat-v1';
+const CACHE_NAME = 'flynn-webchat-v2';
 const token = new URL(self.location.href).searchParams.get('token');
 const withToken = (path) => {
   if (!token) {
@@ -34,17 +34,38 @@ self.addEventListener('fetch', (event) => {
     return;
   }
 
-  event.respondWith((async () => {
-    const cached = await caches.match(event.request, { ignoreSearch: true });
-    if (cached) {
-      return cached;
-    }
+  const requestUrl = new URL(event.request.url);
+  const isNavigation = event.request.mode === 'navigate';
+  const isStaticAsset = requestUrl.origin === self.location.origin
+    && (requestUrl.pathname.startsWith('/lib/')
+      || requestUrl.pathname.startsWith('/pages/')
+      || requestUrl.pathname === '/app.js'
+      || requestUrl.pathname === '/style.css'
+      || requestUrl.pathname === '/index.html'
+      || requestUrl.pathname === '/manifest.webmanifest');
 
+  event.respondWith((async () => {
     try {
-      return await fetch(event.request);
+      const networkResponse = await fetch(event.request);
+      if (isNavigation || isStaticAsset) {
+        const cache = await caches.open(CACHE_NAME);
+        await cache.put(event.request, networkResponse.clone());
+      }
+      return networkResponse;
     } catch {
-      const fallback = await caches.match('/index.html', { ignoreSearch: true });
-      return fallback || new Response('Offline', { status: 503 });
+      const cached = await caches.match(event.request, { ignoreSearch: true });
+      if (cached) {
+        return cached;
+      }
+
+      if (isNavigation) {
+        const fallback = await caches.match('/index.html', { ignoreSearch: true });
+        if (fallback) {
+          return fallback;
+        }
+      }
+
+      return new Response('Offline', { status: 503 });
     }
   })());
 });