The url renders to members as a clickable href. https was enforced only
in the admin Zod action, but RLS lets an admin/board write the row
directly via PostgREST, bypassing Zod, with no DB constraint -- a
malicious admin could store a javascript: URL and XSS members who click.
- Migration 050: CHECK (url ~* '^https://') so the DB is the source of
truth; integration-tested that the service path cannot store
javascript:/http:.
- Member-read action filters with isSafeDuesUrl (defense-in-depth).
