release: 2.12.0: test-email - a test message from Server › Health

Cut without asking, as the owner said on 2026-10-15. A global user sends
one message from postmaster@ the hostname to an address typed; it opens in
the Outbound log, which follows it (the commit before this; mockups
e92769f, e3b2501, 8f0ccf9). Reviewed for security, its low findings fixed.
go vet, go test (26 packages) and make e2e passed on the test server for
that tree. No migration, schema 12.

CHANGELOG [2.12.0]; pins in deploy/docker-compose.yml, README and the guide
(pin, build, the sample restore message); development's "from pin" and
row 38; roadmap row. No tag.

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

docs/roadmap.md

@@ -30,7 +30,7 @@ in `git log` and [CHANGELOG.md](../CHANGELOG.md).
 |---|---|---|---|---|
 | inbound-upstream-result | Inbound › Log shows what the upstream answered: sent, deferred, bounced, with its last reply | shipped `2.10.0` | 7/7 | [plans/inbound-upstream-result.md](plans/inbound-upstream-result.md) |
 | health-setup-checks | Server › Health also checks the certificate's name, Postfix's greeting and the trusted proxy (was preflight) | shipped `2.11.0` | — | — |
-| test-email | Send a test message from the panel (was preflight) | done 2026-10-17, unreleased | — | — |
+| test-email | Send a test message from the panel (was preflight) | shipped `2.12.0` | — | — |
 | inbound-antispam-panel | Inbound antispam journal + allow/deny lists | shipped `2.1.0` | 12/12 | [plans/inbound-antispam-panel.md](plans/inbound-antispam-panel.md) |
 | origin-strict | Refuse a state-changing request that carries neither `Sec-Fetch-Site` nor `Origin` (was csrf-tokens) | shipped `2.10.4` | — | — |
 | backup-reauth | Ask for the account password before a backup or a domain export is downloaded | shipped `2.10.3` | — | — |