Markdown wins the stack argument: the DB scripts run again, seven identities reconciled, and the July 29 cohort lands on the roster

Adding one tool to the registry surfaced that every stack-sync script had been dead since the Astro 7 upgrade — and that Turso had been a stale photocopy of markdown since May 21. Fixed the tooling, declared markdown the source of truth, and caught a roster sync that was about to publish seven duplicate profiles including one called `mail`.