Records what Phase 9 shipped (website#176) and the four decisions the org lead
settled before any of it: mechanism plus SMTP's own synchronous refusal rather
than an API transport; suppression scoped to engagement rules only; an
`address_masked` column added to §4.5's DDL; and the verification gate applied at
enqueue rather than at delivery.
The correction the phase's own text needed: "SMTP has none" is too strong. SMTP
has no asynchronous bounce feed, but a single-recipient send refused at RCPT TO
throws synchronously with the reply code intact, and mailer.js was already
catching that and discarding it.
The defect worth not repeating: `PERMANENT_CODES` is not a bounce classifier. It
answers "is retrying pointless?" and contains EAUTH, so suppressing on it would
have emptied the mailing list the first time an SMTP password expired.
Also records the one thing only the live rig could find — `engagement_sends`
has carried a `bounced` status since §4.5 and nothing had ever written it, so the
Send Log's Bounced filter matched nothing — and answers §7.1 Q1's narrower half.
- ENGAGEMENT.md: Phase 9 "As built", the §4.5 DDL, Q1's narrower half, status header
- BACKEND_DESIGN.md: §3 `engagement_suppressions`, and §7's Deliverability section
Co-Authored-By: Claude <noreply@anthropic.com>
wtclaude
221c5a9c9e