log tailer: expiry, Postfix's time values and refusal lines as Postfix writes them

Expiry (assumptions A-8). Postfix 3.7.11 logs the end of a message's queue
lifetime once per message, "<id>: from=<..>, status=expired, returned to
sender" (src/qmgr/qmgr_active.c, qmgr_active_done_25_generic()), with no
line per recipient; the tailer waited for "to=..., status=expired", which
no Postfix writes, and the sweep closed only queued rows, so such rows
stayed deferred. The tailer now reads qmgr's line (ExpireMessage: each
recipient's newest open row of the id becomes bounced); the sweep closes a
deferred row too when Postfix no longer holds the message, and counts as
missed only a final line (sent, bounced, expiry). The queue listing's '#'
(forced expiry, showq_compat.c showq_message()) is read as a flag (B-PQ1).

Time values (B-PQ10, B-PQ11): conv_time() ported - one number, one
lower-case unit, the parameter's default unit when none (get_def_time_unit:
d for the lifetimes, h for delay_warning_time), the rest ignored; postconf
-h -x expands $name; bounce_queue_lifetime capped at maximal_queue_lifetime
as qmgr_post_init() caps it, so LongestLifetime is the queue lifetime.

Refusals (A-21, A-23, A-24, A-15): smtpd_whatsup() ends the NOQUEUE line
with sasl_username=<login> on an authenticated session; the line is now
matched to its row by client, login and sender, and a line without a login
is no application's. The client= line's login ends at the comma. The
"IPv6:" trim goes (namaddr is built from state->addr). A row recovered from
cleanup's line says that line names the last recipient only.

Stand (2026-10-14, make e2e, exit 0): new expired_message_is_closed -
defer_transports=smtp makes the retry service defer the message, postsuper
-e and postqueue -i force its expiry; mail.log has "<id>:
from=<alerts@sender.e2e.test>, status=force-expired, returned to sender"
and the row goes deferred -> bounced; refusals_show_postfixs_line passes
with the login match. go vet and go test ./... pass on the server.

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

docs/guide.md

@@ -1268,8 +1268,10 @@ chosen. A row identifies its message and nothing more — time,
 sender, recipient, subject and status `queued` (accepted, not yet
 delivered), `sent` (handed off successfully), `deferred` (Postfix is
 retrying), `bounced` (final failure), or refused before it was queued.
-`bounced` is usually Postfix's word; it is the panel's when Postfix no longer
-holds a message and `mail.log` never said what became of it (the log rotated
+`bounced` is usually Postfix's word - a message it gave up on at the end of
+its queue lifetime is `bounced` too, since Postfix returns it to the sender;
+it is the panel's when Postfix no longer holds a message and `mail.log` never
+said what became of it (the log rotated
 away while the panel was down, or was not readable) - the panel then closes
 the row as a failure rather than show a delivery it cannot evidence, and
 counts that it did. A