base-trixie: the image on Debian trixie, Postfix 3.10.13; Received: hidden on 465/587

The runtime base is debian:trixie-slim, the build stage golang:1.26-trixie:
Postfix 3.10.13 with upstream's 2026 security fixes up to the August
batch, libmilter 8.18.1, OpenSSL 3.5. Every citation of another program in
code, scripts and documents was re-read against the trixie sources
(dev/upstream; bookworm's kept in dev/upstream-bookworm) and updated;
development.md's cited-package table holds the trixie versions.

What the re-reading changed in behaviour:
- logtail: reject lines with sasl_method/sasl_username/sasl_sender
  (smtpd_check.c:1019-1026); cleanup's "removed (canceled)" forgets a
  port-25 id (cleanup_api.c:363-364).
- internal/postfix/retry.go reads postconf's stdout only: since 3.9 a
  deprecated-parameter warning on stderr made one value too many and the
  panel fell back to the compiled-in retry policy.
- logrotate-loop.sh: logrotate 3.22 exits 1 when it ignores a config;
  the loop refuses on that output whatever the status.
- postfix-config.sh: cyrus_sasl_config_path set explicitly (bookworm's
  07_sasl_config.diff is gone); maillog_file_permissions=0640; mynetworks
  explicit; Dockerfile: SYNC_CHROOT= in /etc/default/postfix,
  opendkim-tools dropped, openssl named, systemd-standalone-sysusers so
  cron does not bring the whole of systemd.
- The selfpost group is 10998, outside the system range 100-999: in
  trixie a package took 998 and the build failed (owner's decision:
  a conflict-free id, the distribution's own ids untouched). The
  entrypoint hands /data back by name when the user or the group differs.
  Guide, backup refusal text, help (design commit 68ec8b2), e2e.
- smtpd_hide_client_session=yes on smtps and submission (owner's
  decision): Received: names no client, TLS, login or protocol; port 25
  keeps the full header. e2e checks both.
- test/upstream/opendkim-probe.sh makes keys with openssl genrsa.

Tests: on the server, make e2e exit 0 (674 s, the image built on trixie),
go vet + go test 27 packages ok. CHANGELOG [Unreleased], guide,
architecture.md, security.md, roadmap.

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

internal/logtail/offset.go

@@ -17,7 +17,7 @@ import (
 
 const (
 	// fingerprintSize is how many bytes from the head of the log identify it.
-	// Postfix writes a timestamped line per event (Postfix 3.7.11,
+	// Postfix writes a timestamped line per event (Postfix 3.10.13,
 	// src/util/msg_logger.c, msg_logger_print(): "%b %d %H:%M:%S" on every
 	// record), so the first 512 bytes are
 	// effectively unique per log generation — enough to tell "the file we were
@@ -130,7 +130,7 @@ func (t *tracker) resume(f *os.File) int64 {
 
 // readRotated reads, when the log was rotated while the panel was down, the
 // rest of the file the saved place belongs to: logrotate renamed it to
-// mail.log.1 (delaycompress leaves it plain - logrotate 3.21.0, logrotate.c,
+// mail.log.1 (delaycompress leaves it plain - logrotate 3.22.0, logrotate.c,
 // prerotateSingleLog()), and what Postfix wrote there
 // between the panel's stop and the rotation - deliveries, refusals, deferrals -
 // was otherwise never read (audit 2026-10-12, stage 2b). It is read from the