Verifies that HandleFailedTOTPAuth locks the account after 10 rolled-back
caller sessions (the regression from GHSA-fgfv-pv97-6cmj), and that the
persisted password reset token can unlock the account via ResetPassword.
Store used TOTP passcodes in the keyvalue store after successful
validation. On subsequent validation attempts, check if the passcode
was already used for the same user and reject it with
ErrTOTPPasscodeUsed. This prevents replay attacks where an intercepted
TOTP code could be reused within its 30-second validity window.
Add TestTOTPPasscodeCannotBeReused which verifies that a valid TOTP
passcode cannot be used twice within its validity window. Also add
ErrTOTPPasscodeUsed error type for the new behavior.
kolaente