Ham Lab logo: PWA icon set + login screen

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

web/public/sw.js

@@ -1,5 +1,5 @@
 // Ham Lab service worker: cache hashed assets, never the API, network-first for the shell.
-const CACHE = 'hamlab-v1';
+const CACHE = 'hamlab-v2';
 self.addEventListener('install', () => self.skipWaiting());
 self.addEventListener('activate', (e) => {
   e.waitUntil(caches.keys().then((ks) => Promise.all(ks.filter((k) => k !== CACHE).map((k) => caches.delete(k)))).then(() => self.clients.claim()));