findings of the reviews of audit stage 2b

Technical review (Opus) and security review (Fable) of 5be109b..5154bba;
reports in the session's scratchpad. Nothing above low from security; one
bug and three risks from the technical review. Migration 0009 is not
deployed, so it was extended.

- Bug: two refusals of one second swapped their NOQUEUE lines (each line
  went to the newest lineless row). AttachRefusalLine now matches the
  client address too (send_log.client_ip, written by the journal milter -
  Postfix's line names the client and the sender, never the login: the
  sasl_username part of the pattern never matched and could be fed by HELO,
  security F1/F2), takes the nearest row in time and the oldest of equals,
  and a line already on a row goes on no other (security F6).
- Waiting lines and recoveries lived only in memory while the saved offset
  moved past them: a stop within 30 s lost them. The tracker now never saves
  an offset past the oldest waiting item in its file (tracker.hold,
  refusalLines.oldest) - for a recovery, the client= line that names its
  login - so they are read again; the "once" guards make that harmless.
- A recovered row whose login the tailer did not see was nobody's: its
  domain_id falls back to the envelope domain's.
- The fingerprint's file identity is the inode alone: the device number can
  change across a host reboot and make the same log look rotated.
- A refused row carries its queue id; UpdateStatus's "newest row" now skips
  refused rows, so a later message with that id does not flip it to sent.
- The alive mark: its age is read first and kept from then on, so asking
  supervisord for 30 s cannot make it stale; the entrypoint removes it with
  the sockets - a container restart is not the check's downtime, and a mark
  from before would have counted the whole outage as "≈".
- Security F3: the sender check prints no ";" of the client's in the From:
  text of its reply, and the tailer reads the envelope after the first ";"
  - Postfix's own text.
- A refused row with a queue id and no stored lines says so (it was told the
  mail.log text of 2.2.0); the fact's em dash is the house hyphen.
- Docs: architecture (client address, no login), guide § Health (warns on
  either count), help topics log and sender-check (design 1ca87f2).
- e2e: refusals_show_postfixs_line wants the refusal's own sender in the
  line; refusal_recovered_from_the_log waits past the tailer's 30 s and
  checks that a refusal the panel wrote got no recovered twin.

Not changed, written down: review 9 (mail.log.1 read to its end at that
moment; postlogd may still write to it until the reload), 10 (a log under
512 bytes has no fingerprint, so places fall back to time briefly after a
rotation), 6 (a 451 at MAIL FROM of another milter reads the same - the
client and sender must match too now), security F5/F12 (info). Review 12:
the refused and closed-by-the-panel variants of out-message were shown to
the owner as pictures of the real templates, not drawn in out-message.html:
the guard ties every drawn screen to a page of the engine, and a variant
has the page's outline.

Evidence on the test server for this tree: go vet clean, go test ./... 23
packages ok, make e2e exit 0 (refusal_recovered_from_the_log 70 s).

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

internal/logtail/offset.go

@@ -47,9 +47,16 @@ type tracker struct {
 	behind bool
 	prev   store.LogtailState
 
-	// line is the place of the line being handled: set by follow and
-	// readRotated before each call of handle.
-	line Place
+	// line is the place of the line being handled, lineStart the offset it
+	// starts at: set by follow and readRotated before each call of handle.
+	line      Place
+	lineStart int64
+
+	// hold, when set, names the earliest place in a file that something read
+	// from the log still waits on (a refusal's line, a refusal to recover):
+	// no offset past it is saved, so a stop - clean or not - before the wait
+	// is over reads it again (review of stage 2b).
+	hold func(fp string) (Place, bool)
 }
 
 // Place is where a line of the log ends: the fingerprint of its file and the
@@ -158,6 +165,7 @@ func (t *tracker) readRotated(handle func(string)) bool {
 	r := bufio.NewReader(f)
 	for {
 		line, err := r.ReadString('\n')
+		t.lineStart = end
 		end += int64(len(line))
 		if line != "" {
 			t.line = Place{FP: fp, End: end}
@@ -198,6 +206,11 @@ func (t *tracker) adopt(f *os.File) {
 // record persists offset, at most once per persistInterval unless force is set
 // (rotation and shutdown, where the write must not be skipped).
 func (t *tracker) record(f *os.File, offset int64, force bool) {
+	if t.hold != nil {
+		if p, ok := t.hold(t.fp); ok && p.End < offset {
+			offset = p.End
+		}
+	}
 	if offset == t.saved {
 		return
 	}