Review: keep the desk's notification ids so lost answers are said again in place (issue 384)

dunst.started says the notifier's bundle started again: the notifications stay on screen and only the
answers they waited for are lost. Forgetting their ids made the router's message a second popup beside a
dead one. The desk now keeps the ids and says answers-lost-at; the router's message replaces each
notification in place.

Whether a message is said again is now its own (last said before the answers were lost), so a router
that started after the loss still says it and a repeated standing says nothing. It is sent to the desk
directly, not through the outbox, whose failure path moves a warning to Telegram; a failed send is tried
again at the next standing.

modules/messenger/README.md

@@ -18,13 +18,13 @@ channel's client and no channel's secret.
   is the channel's own, said on `intake.standing`.
 - **Keeps its state on the bus** (ADR 0201): `open` and `sent` (the messages), `asks` (every ask, closed ones
   for 30 days), `identities` (the operator's linked accounts, one per kind, and a link asked for).
-- **A screen made new is said again from here, never from a channel's memory** (issue 384,
-  `cmd/messenger/restart.go`): a channel whose screen was lost — the desk's notifier started again — says so
-  in its standing (`shows-since`), and the router says again on that kind what is still open and asked there,
-  one message per problem under its handle with the words and answers of now; what is silenced is edited to
-  say so, with no answers and no urgency; what ended never comes back. Each move of `shows-since` is acted on
-  once, and waits while the kind cannot send rather than going to another channel. Telegram's messages stay in
-  the chat and it says no `shows-since`.
+- **Lost answers are said again from here, never from a channel's memory** (issue 384,
+  `cmd/messenger/restart.go`): a channel whose messages' answers were lost — the desk's notifier started
+  again — says when in its standing (`answers-lost-at`). The router says again on that kind, directly and not
+  through the outbox, each message that is still open, asked there and last said before that time: one per
+  problem, under its handle, with the words and answers of now, so it replaces the message in place. What is
+  silenced is edited to say so, with no answers and no urgency; what ended never comes back. A kind that cannot
+  send waits; it never goes to another channel. Telegram's answers are never lost and it says no time.
 
 ## Asks, answers and warrants (novox/hq ADR 0259)