audit 4: findings of the two reviews

- Two inbound domains on one upstream could never change its TLS mode,
  each save refused for the other (medium): SetTransportAs changes the
  mode for every domain on the upstream when the one saving may change
  them all; a domain user who may not is refused with the mode, not the
  other tenant's domain name (security F1: the first version named it).
- A deletion's leftover DKIM key is removed by Resync (Reload
  configuration, a restore's first start) for names no domain has.
- The backup's write deadline moves before Check.
- hasUnsavedEdit skips password and file fields and compares a multiple
  select's options; htmx.config.timeout 30 s, so a refresh never answered
  ends and is tried again; a failed refresh's promise is handled.
- An empty filtered Outbound log says no message matches the filters.
- The dummy bcrypt hash is made at start; a DMARC part over 8 MiB is
  refused for its size like the other two limits.
- Health's Configuration box says what Reload writes (design first,
  32dfe4a).
- Docs: CHANGELOG, guide § Inbound, security.md (the shared upstream's
  mode, the profile form's "username taken"), architecture.md (owed to an
  address), the plan's notes corrected.
Tests: the shared upstream (service, handler), the leftover key, all eight
Health boxes ordered, the subject from before migration 0011, the new JS
cases.

Tested on the test server: go vet + go test of 25 packages, make e2e (all
pass, 636 s) on this tree.

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

docs/guide.md

@@ -1016,9 +1016,10 @@ reports](#dmarc-reports).) Outbound 465/587 is unchanged.
 **Panel** (`/inbound/domains`): the global role adds and deletes domains. On a
 domain's page, set the upstream host/port and TLS to that hop (opportunistic /
 required / off), and choose recipients. An upstream has one TLS mode: Postfix
-keeps the TLS policy per next hop, not per domain, so a second domain sent to
-the same host and port with another mode is refused, naming the domain that
-already uses it. Recipients are an allow-list, or any address at that
+keeps the TLS policy per next hop, not per domain, so the mode saved for one
+domain is the mode of every domain forwarded to the same host and port, and
+they are changed with it; a *domain* user who does not manage all of them is
+refused, and told the mode in use. Recipients are an allow-list, or any address at that
 domain. Inbound domains are assigned to a user with the *domain* role
 separately from outbound ones (see [Users](#users)); such a user sees and
 changes the upstream and recipients of the inbound domains assigned to them,