audit: stage 2c - what was taken on trust, read in Postfix's source

Owner, 2026-10-14, after the rule "do not guess how code works when its
documentation or source can be read": "Есть ли ещё у нас места, где мы
угадывали?". The inventory found four: qmgr's expiry against the queue
lifetime (a margin in queued_over_lifetime), postlogd after a rename (the
rotation window), the stale smtpd after a reload (measured, not
understood), and the NOQUEUE line's fields (two fixtures carry a
sasl_username Postfix does not write, one presented as seen on the stand).
A line in stage 2c reads Postfix 3.7.11 for them, records what is read,
fixes the fixtures and the code where they disagree. Plan 66 lines.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/audit-2026-10-12.md

@@ -873,6 +873,20 @@ those after it move up one patch number each.
    shared files of lines (`from-lines-passed.txt`, `from-lines-other.txt`)
    are kept: the second one's test becomes "never signed for {other}"
    rather than "refused". - **Opus**
+- [ ] **What was taken on trust, read in Postfix's source** (owner,
+   2026-10-14: "запиши себе правило не гадать, как работает код, если можно
+   посмотреть в его документацию или исходный код"; then "Есть ли ещё у нас
+   места, где мы угадывали?"). Postfix 3.7.11 - the image's version - read
+   for: (1) when qmgr expires a message against maximal_queue_lifetime - the
+   "+ maximal_backoff" margin of queued_over_lifetime is a guess; (2) whether
+   postlogd goes on writing to the renamed mail.log until the reload - the
+   rotation window the deferred tailer fix is about; (3) why an smtpd from
+   before a reload takes one more connection, and for how long - measured
+   (under 2 s), not understood; (4) the NOQUEUE reject line's fields - two
+   test fixtures carry a sasl_username= that Postfix does not write, one
+   of them presented as seen on the stand; they are corrected. What is read
+   goes into architecture.md with the file it is in; where it contradicts
+   the code, the code is fixed in this stage. - **Opus**
 - [ ] Docs and wording: help topic sender-check and guide § Who an
    application may send as (mockup first), security.md § Mail path,
    CHANGELOG. - **Sonnet**