feat(web+android): search play queues only the tapped song (radio fills the rest)

Playing a song from search results queued the whole result list. Now it plays only
the clicked song; Radio mode, if on, fills the rest — closer to Spotify. Both
platforms already trigger a radio top-up on the first track (web playQueue →
fillRadioQueue; Android onMediaItemTransition → checkRadioRefill), so no extra wiring
is needed. Album/playlist play still queues the full list. Bump SW cache to ns-v44.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

public/sw.js

@@ -1,4 +1,4 @@
-const CACHE = 'ns-v43';
+const CACHE = 'ns-v44';
 const PRECACHE = ['/', 'index.html', 'manifest.json', 'icon.svg'];
 const SKIP_PATHS = ['/rest/stream', '/rest/download', '/config.js'];
 // Auth token params stripped from cache keys so artwork survives across sessions/token refreshes.