frontend/sw.js

const CACHE_NAME = 'urbanflow-v4';
const ASSETS = [
  './css/initial.css',
  './css/vehicles.css',
  './css/shared.css',
  './css/auth.css',
  './assets/shuriken.png',
  './assets/shurkien_b.png',
  './assets/uf_rf.png'
];

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

self.addEventListener('fetch', (e) => {
  const url = new URL(e.request.url);
  
  // NEVER cache WebSockets or API calls
  if (url.pathname.includes('/ws/') || url.pathname.includes('/reports/') || url.pathname.includes('/bundle/')) {
    return;
  }

  e.respondWith(
    fetch(e.request).catch(() => caches.match(e.request))
  );
});