composer audit reported 37 advisories across 15 packages, including
high-severity ones in symfony/security-http. Ran composer update
within the existing 7.4.* constraints - composer audit now reports
zero advisories. Also adds symfony/rate-limiter, needed for login
throttling and invite-code rate limiting in the next commit.
Flex removed a stale, non-functional sendgrid notifier config left
over from before the app switched to Mailgun as part of the sync.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
