Re-check the 2026-10-03 catalog go-live from outside:
  1. sha256sum -c SHA256SUMS
  2. python3 ../_publisher/verify_publisher.py.txt ../catalog-go-live-2026-10-03 ../_publisher/catalog-go-live-2026-10-03.json
  3. curl -s -H 'Accept: application/json' https://cainstudio.online/catalog   (availability)
  4. with a free key from https://cainstudio.online/signup, call any service under
     https://cainstudio.online/<service>/... ; a second key must not see the first key's data.