fix(embed): Spotify API via CSP whitelist + faster fallback
Diagnosis (measured live): the loader open.spotify.com (200) loads the real
API bundle from embed-cdn.spotifycdn.com, which was NOT in our CSP scriptSrc
→ API never init → 8s wait before the bare iframe = "sluggish". Not an
ad-blocker issue.
- CSP: *.spotifycdn.com added to scriptSrc + connectSrc (+ *.scdn.co).
- Spotify API timeout 8s → 4s so the iframe fallback appears quickly if the
API still doesn't initialise (CDN 503 / origin gating).
buster embed-player.js?v=5.
Co-Authored-By: Claude <noreply@…>