Send Early Purge Otp

Request a code to clear a previous erasure and re-join

For someone who asked to be erased and now wants to sign up again: their old record still holds this email/phone until the retention window ends, which blocks a fresh sign-up. Proving they control the contact lets us purge the old record immediately.

Always 202 with an empty body, on the same anti-enumeration grounds as the restore flow. A code is only ever sent to the contact on file, and only when a blocking erased record actually exists.