milter, postfix, app, domain: cite the source of what they rely on (assumptions part B)

Comments only, no behaviour changed. go-milter v0.4.1 (session.go: one
session per connection, replaced after a non-continue reply; macros per
stage), Postfix 3.7.11 (milter8.c, smtpd_check.c
reject_auth_sender_login_mismatch(), mail_addr_find.c, showq_compat.c,
mail_conf_time.c, mail_params.h), Cyrus SASL 2.1.28 (saslpasswd.c,
plugins/sasldb.c: deleting a missing login is not an error), OpenDKIM
2.11.0~beta2 (opendkim-db.c, opendkim-genkey), Berkeley DB 5.3 db_dump,
rspamd 3.11.0. Comments that claimed what the source denies are corrected
(sasldb keeps the password as given, not hashed; an embedded newline is
kept, not truncated; rspamd sorts symbols by absolute weight); fixtures say
seen or composed. The sender check's From: parsing gets no citations: it is
replaced by the port of OpenDKIM's dkim_mail_parse next.

Contradictions left for their own commits: B-G5 cleanAddress, B-PS1 first
key wins, B-PQ1 the forced-expire flag, B-PQ10/PQ11 Postfix's time units.

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

internal/postfix/queue_test.go

@@ -12,7 +12,8 @@ import (
 
 // TestFakePostqueue is not a test: it is the fake `postqueue -p` the tests
 // below run in place of the real one, writing SP_FAKE_POSTQUEUE_BYTES bytes of
-// queue entries.
+// queue entries composed by hand after the layout of Postfix 3.7.11's
+// src/postqueue/showq_compat.c.
 func TestFakePostqueue(t *testing.T) {
 	if os.Getenv("SP_FAKE_POSTQUEUE") != "1" {
 		t.Skip("helper process")
@@ -73,10 +74,12 @@ func TestQueueIDsReadsAListingUnderTheCap(t *testing.T) {
 }
 
 // The reconcile sweep decides whether a message is still Postfix's problem, so
-// the parser must pick queue ids out of a real listing and nothing else out of
-// it: not the header, not the byte-count trailer, and above all not a deferred
-// entry's reason line, which — unlike the recipient lines — starts at the left
-// margin just as an entry does.
+// the parser must pick queue ids out of a listing and nothing else out of it:
+// not the header, not the byte-count trailer, and above all not a deferred
+// entry's reason line. The listing is composed by hand. Postfix 3.7.11
+// (src/postqueue/showq_compat.c, showq_message()) right-aligns a reason to
+// column 76, so it reaches the left margin only when it is 76 characters or
+// longer; the one here is put at the margin as the hard case.
 func TestParseQueueIDs(t *testing.T) {
 	listing := `-Queue ID-  --Size-- ----Arrival Time---- -Sender/Recipient-------
 3C5B04E6C1*     446 Fri Aug  8 10:12:31  app@example.com