The console offers a single mail.password pointing at one SMTP mailbox,
which is nowhere near enough for five sending addresses. A mailbox is
address, display name, username and password; five of them as registry
entries would be twenty secrets named mail.support.username, and the
question of which mail sends from which address would still have no home.
Send-only stays usable because every message carries Reply-To on its own
mailbox, so a customer's reply lands in a mailbox someone reads. That is
what makes IMAP unnecessary rather than merely deferred.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>