Enable PWA

public/service-worker.js

@@ -1,37 +1,67 @@
-const CACHE_NAME = 'time-tracker-app-v1';
+const CACHE_NAME = 'time-tracker-app-v2';
 const urlsToCache = [
   '/',
-  '/static/js/bundle.js',
-  '/static/css/main.css',
+  '/index.html',
   '/manifest.json',
   '/favicon.ico',
-  '/logo_ficosa.png'
+  '/logo192.png',
+  '/logo512.png'
 ];
 
-// Install event - cache essential assets
+// Install event - cache essential static assets
 self.addEventListener('install', (event) => {
+  // Skip waiting to activate immediately
+  self.skipWaiting();
+  
   event.waitUntil(
     caches.open(CACHE_NAME)
       .then((cache) => {
         console.log('Opened cache');
+        // Use addAll for guaranteed files. If these fail, SW won't install.
+        // We omit JS/CSS because CRA uses hashed filenames in production.
         return cache.addAll(urlsToCache);
       })
   );
 });
 
-// Fetch event - serve cached content when offline
+// Fetch event - Stale-while-revalidate strategy for most requests
 self.addEventListener('fetch', (event) => {
+  // Only handle GET requests
+  if (event.request.method !== 'GET') return;
+  
+  // Skip cross-origin requests
+  if (!event.request.url.startsWith(self.location.origin)) return;
+
   event.respondWith(
     caches.match(event.request)
-      .then((response) => {
-        // Return cached version or fetch from network
-        return response || fetch(event.request);
+      .then((cachedResponse) => {
+        const fetchPromise = fetch(event.request).then((networkResponse) => {
+          // Dynamically cache successful GET requests
+          if (networkResponse && networkResponse.status === 200) {
+            const responseToCache = networkResponse.clone();
+            caches.open(CACHE_NAME)
+              .then((cache) => {
+                cache.put(event.request, responseToCache);
+              });
+          }
+          return networkResponse;
+        }).catch(() => {
+          // If network fails and we have no cache, return the cached index.html for navigation requests (SPA fallback)
+          if (event.request.mode === 'navigate') {
+            return caches.match('/');
+          }
+        });
+
+        return cachedResponse || fetchPromise;
       })
   );
 });
 
 // Activate event - clean up old caches
 self.addEventListener('activate', (event) => {
+  // Take control of all clients immediately
+  event.waitUntil(self.clients.claim());
+  
   event.waitUntil(
     caches.keys().then((cacheNames) => {
       return Promise.all(