sw.js

// Simple cache-first service worker so the installed PWA runs offline.
const CACHE = 'firered-v1';

self.addEventListener('install', () => self.skipWaiting());
self.addEventListener('activate', (e) => e.waitUntil(self.clients.claim()));

self.addEventListener('fetch', (e) => {
  if (e.request.method !== 'GET') return;
  e.respondWith(
    caches.open(CACHE).then(async (cache) => {
      const hit = await cache.match(e.request);
      const net = fetch(e.request)
        .then((res) => {
          if (res && res.ok) cache.put(e.request, res.clone());
          return res;
        })
        .catch(() => hit);
      return hit || net;
    })
  );
});