journal milter: recipients as Postfix logs them, once each

The row's recipient has to be the address Postfix writes in to=<..> or
orig_to=<..>, or the delivery line finds no row and the sweep closes it as
bounced. Postfix 3.7.11 hands the milter the RCPT argument as the client
wrote it (smtpd.c, milter_argv(); extract_addr() leaves it), go-milter
v0.4.1 trims "<>" and drops the ESMTP parameters (session.go, case
CodeRcpt) - so cleanAddress's cut at the first blank broke a quoted local
part (B-G5). Postfix keeps the address in internal form (tok822: quotes
off, backslash escapes taken) and logs it external
(info_log_addr_form.c, quote_822_local(): quoted again only when not a
dot-string); recipientAsLogged does the same, "ab"@x -> ab@x, "a b"@x
stays. A recipient given twice in any case is one row: cleanup drops the
duplicate, comparing folded (cleanup_out_recipient.c, been_here(),
BH_FLAG_FOLD; A-31). A rewritten recipient is matched by orig_to=, which
log_adhoc() writes only when it differs (A-9). The store's
case-insensitive match stays, now with its reason from the source (D-S20).

Stand (2026-10-14, make e2e, exit 0): new recipients_as_postfix_logs_them
- RCPT TO "x y"@, "ab"@ and "X Y"@ sink.e2e.test give two rows, "x
y"@sink.e2e.test and ab@sink.e2e.test, both sent. go vet and go test ./...
pass on the server; a unit test drives the milter through go-milter's own
client.

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

test/e2e/smtp_client.go

@@ -23,6 +23,7 @@ const smtpsAddr = "127.0.0.1:20465"
 type sendAttempt struct {
 	authLogin, authPassword string
 	from, to                string
+	moreTo                  []string // further RCPT TO, after to
 	headerFrom              string
 	subject, body           string
 }
@@ -133,10 +134,12 @@ func attemptSend(a sendAttempt) sendResult {
 		_ = c.Quit()
 		return res
 	}
-	if err := c.Rcpt(a.to); err != nil {
-		res.rcptErr = err
-		_ = c.Quit()
-		return res
+	for _, to := range append([]string{a.to}, a.moreTo...) {
+		if err := c.Rcpt(to); err != nil {
+			res.rcptErr = err
+			_ = c.Quit()
+			return res
+		}
 	}
 	w, err := c.Data()
 	if err != nil {