ADMIN_BASE pointed at thefulfillment.org (a parked domain) instead of
the actual Ghost host blog.the-fulfillment.org, and NEWSLETTER_SLUG was
"the-fulfillment" instead of Ghost's auto-generated "default-newsletter"
(the display name "The Fulfillment" doesn't determine the slug).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
