fix(web): cleaner German fan-count format (559.542 instead of "559,5 Tsd.")

fmtCount now shows the full grouped number below a million (toLocaleString de-DE) and only
compacts millions ("1,2 Mio."). The old "Tsd." form read awkwardly on the artist hero. SW ns-v53.

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

public/sw.js

@@ -1,4 +1,4 @@
-const CACHE = 'ns-v52';
+const CACHE = 'ns-v53';
 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.