sw.js

/* BitBench service worker — cache-first for the app shell, offline fallback */
const CACHE = 'bitbench-v10';
const ASSETS = [
  './',
  './index.html',
  './manifest.webmanifest',
  './icon.svg'
];

self.addEventListener('install', e => {
  e.waitUntil(
    caches.open(CACHE).then(c => c.addAll(ASSETS)).then(() => self.skipWaiting())
  );
});

self.addEventListener('activate', e => {
  e.waitUntil(
    caches.keys()
      .then(keys => Promise.all(keys.filter(k => k !== CACHE).map(k => caches.delete(k))))
      .then(() => self.clients.claim())
  );
});

self.addEventListener('fetch', e => {
  if (e.request.method !== 'GET') return;
  e.respondWith(
    caches.match(e.request).then(cached => {
      if (cached) return cached;
      return fetch(e.request).then(res => {
        const clone = res.clone();
        caches.open(CACHE).then(c => c.put(e.request, clone));
        return res;
      }).catch(() => caches.match('./index.html'));
    })
  );
});