Supabase refuses a sign-up with 429 over_email_send_rate_limit once the
project's hourly email allowance is spent, and with a 500 "Error sending
confirmation email" when the mail server fails. No account is created in
either case, but the dialog said "Too many attempts. Wait a moment and try
again." (or "Sign up failed"), which sends people back to a wall. Name
the real problem and point at Discord, which needs no email.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>