New headphones app icon set, hardened streaming and playback, download removal controls

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

sw.js

@@ -1,7 +1,7 @@
 // Keeps the app shell so the player opens with no connection. Audio is stored separately by the page (IndexedDB).
 // Service workers only run on HTTPS (or localhost).
-const CACHE = 'shell-v1';
-const STATIC = ['/manifest.webmanifest', '/icon-180.png', '/icon-192.png', '/icon-512.png'];
+const CACHE = 'shell-v2';
+const STATIC = ['/manifest.webmanifest', '/icon-180.png', '/icon-192.png', '/icon-512.png', '/icon-32.png'];
 
 self.addEventListener('install', e => {
   e.waitUntil(caches.open(CACHE).then(c => Promise.all(['/', ...STATIC].map(u => c.add(u).catch(() => {})))).then(() => self.skipWaiting()));