Añadidos manifiestos para PWA.

sw.js

@@ -0,0 +1,77 @@
+const CACHE_VERSION = 'v1';
+const CACHE_NAME = `fermdez-games-${CACHE_VERSION}`;
+const CORE_ASSETS = [
+  '/',
+  '/index.html',
+  '/media/favicon.ico',
+  '/manifest.webmanifest'
+];
+
+self.addEventListener('install', event => {
+  event.waitUntil(
+    caches.open(CACHE_NAME)
+      .then(cache => cache.addAll(CORE_ASSETS))
+      .then(() => self.skipWaiting())
+  );
+});
+
+self.addEventListener('activate', event => {
+  event.waitUntil(
+    (async () => {
+      const keys = await caches.keys();
+      await Promise.all(keys.map(k => k !== CACHE_NAME && caches.delete(k)));
+      await self.clients.claim();
+    })()
+  );
+});
+
+const cacheFirst = async (req) => {
+  const cache = await caches.open(CACHE_NAME);
+  const cached = await cache.match(req);
+  if (cached) return cached;
+  const resp = await fetch(req);
+  if (resp && resp.status === 200 && req.method === 'GET') {
+    cache.put(req, resp.clone());
+  }
+  return resp;
+};
+
+const networkFirst = async (req) => {
+  const cache = await caches.open(CACHE_NAME);
+  try {
+    const resp = await fetch(req);
+    if (resp && resp.status === 200) {
+      cache.put(req, resp.clone());
+    }
+    return resp;
+  } catch (err) {
+    const cached = await cache.match(req);
+    if (cached) return cached;
+    if (req.mode === 'navigate') {
+      return cache.match('/index.html');
+    }
+    throw err;
+  }
+};
+
+self.addEventListener('fetch', event => {
+  const { request } = event;
+  if (request.method !== 'GET') return;
+  const accept = request.headers.get('accept') || '';
+  const url = new URL(request.url);
+  const isSameOrigin = url.origin === self.location.origin;
+  const isHTML = accept.includes('text/html');
+  const isStaticAsset = /\.(?:css|js|png|jpg|jpeg|svg|ico|webmanifest|mp3|wav)$/.test(url.pathname);
+  if (isHTML) {
+    event.respondWith(networkFirst(request));
+  } else if (isSameOrigin && isStaticAsset) {
+    event.respondWith(cacheFirst(request));
+  }
+});
+
+// Optional: handle message to trigger skipWaiting from client
+self.addEventListener('message', event => {
+  if (event.data && event.data.type === 'SKIP_WAITING') {
+    self.skipWaiting();
+  }
+});