fix: switch service worker to network-first for HTML

Cache-first was serving stale index.html after deploys, causing chunk
404s and "Application error" for all users until hard refresh. Now
HTML always fetches from network (offline falls back to cache), while
content-hashed _next/static/* assets stay cache-first. Bumps cache
name to v2 to evict broken v1 cache for existing users.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Copexit

public/sw.js

@@ -1,13 +1,11 @@
-const CACHE_NAME = "ami-exposed-v1";
+const CACHE_NAME = "ami-exposed-v2";
 const OFFLINE_URL = "/offline.html";
 
-const PRECACHE_URLS = ["/", "/offline.html"];
-
 self.addEventListener("install", (event) => {
   event.waitUntil(
     caches
       .open(CACHE_NAME)
-      .then((cache) => cache.addAll(PRECACHE_URLS))
+      .then((cache) => cache.addAll([OFFLINE_URL]))
       .then(() => self.skipWaiting()),
   );
 });
@@ -28,42 +26,48 @@ self.addEventListener("activate", (event) => {
 });
 
 self.addEventListener("fetch", (event) => {
-  // Only handle GET requests
   if (event.request.method !== "GET") return;
 
-  // Skip all cross-origin requests (API calls, custom endpoints, etc.)
   const url = new URL(event.request.url);
-  if (url.origin !== self.location.origin) {
-    return;
-  }
 
-  event.respondWith(
-    caches.match(event.request).then((cached) => {
-      if (cached) return cached;
+  // Skip cross-origin requests (API calls, custom endpoints, etc.)
+  if (url.origin !== self.location.origin) return;
 
-      return fetch(event.request)
-        .then((response) => {
-          // Cache successful responses for static assets
-          if (
-            response.ok &&
-            (url.pathname.endsWith(".js") ||
-              url.pathname.endsWith(".css") ||
-              url.pathname.endsWith(".svg") ||
-              url.pathname.endsWith(".woff2") ||
-              url.pathname.endsWith(".json"))
-          ) {
+  // Content-hashed assets (_next/static/*) are immutable - cache-first is safe
+  if (url.pathname.startsWith("/_next/static/")) {
+    event.respondWith(
+      caches.match(event.request).then((cached) => {
+        if (cached) return cached;
+        return fetch(event.request).then((response) => {
+          if (response.ok) {
             const clone = response.clone();
             caches.open(CACHE_NAME).then((cache) => cache.put(event.request, clone));
           }
           return response;
-        })
-        .catch(() => {
-          // Offline fallback for navigation requests
+        });
+      }),
+    );
+    return;
+  }
+
+  // HTML and everything else: network-first, fall back to cache
+  event.respondWith(
+    fetch(event.request)
+      .then((response) => {
+        if (response.ok) {
+          const clone = response.clone();
+          caches.open(CACHE_NAME).then((cache) => cache.put(event.request, clone));
+        }
+        return response;
+      })
+      .catch(() => {
+        return caches.match(event.request).then((cached) => {
+          if (cached) return cached;
           if (event.request.mode === "navigate") {
             return caches.match(OFFLINE_URL);
           }
           return new Response("Offline", { status: 503 });
         });
-    }),
+      }),
   );
 });