Ticket drop monitor

Generated addresses must actually receive mail — signup needs the email OTP.

Jobs run one at a time — signup is bound by SMS supply and sign-in is velocity-limited by TM, so parallel batches trip limits faster without finishing sooner. Cancel finishes the account in flight rather than killing it: a signup interrupted between "TM created it" and "we stored the password" leaves an account that exists, cost money, and can never be used.

Expect ~$0.117 and ~46s per account. PHONE_VERIFICATION_LIMIT_REACHED (~30/day) and identity redirect bad location (~40 sign-ins/evening) are TM's limits, not faults — retry later.