The ics library's url validator requires a scheme (https://...), but
production's FRONTEND_URL/APP_BASE_URL was configured without one, so
createEvent() rejected every request before generating a .ics file.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PAwumFeBwx6XSsQXp8Nfqt