fix(artist pin): esc() crashed on numeric Deezer id; move pin button to banner top-right

- esc() now coerces to string first (String(s ?? '')), so passing a number (e.g. the
  Deezer artist id in the pin picker) no longer throws 'replace is not a function'.
- The '⚙ Falscher Künstler?' button moved from under the fan count to the top-right
  of the artist banner (absolute, on the hero). SW cache -> ns-v75.

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

public/sw.js

@@ -1,4 +1,4 @@
-const CACHE = 'ns-v74';
+const CACHE = 'ns-v75';
 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.