Security Enhancements

[ryanstpierre]

Description\nImplement additional security measures to protect the site and form submissions.\n\n## Tasks\n- Implement rate limiting for the registration form\n- Add CSRF protection for form submissions\n- Review and enhance HTTP security headers\n- Implement bot protection for the form\n\n## Technical Notes\nCloudflare provides several security features that can be leveraged:\n- Rate limiting rules\n- Turnstile for bot protection\n- Security headers can be enhanced in _headers file\n\n## Priority\nHigh