feat(sweep): close the aged FYI backlog without a human in the loop

A notice needs no answer, but it is still re-injected at every session
start until someone closes it by hand. Across enough repositories that
hand-closing IS the manual work the mailbox was meant to remove, and the
pending count -- the operator's only signal -- drowns in messages that
were never going to be acted on: 9 of 22 pending messages across 12
mailboxes were pure notices when this was written.

coord-sweep.sh closes exactly one mechanically decidable class:
reply-expected: no, older than a grace window (default 14 days). A
message that owes a reply is never touched, at any age, with any flag --
answering it would mean deciding something on the receiving repo's
behalf, which is the one thing this system exists to prevent.

Four properties are load-bearing, not incidental:

- Dry-run is the default, inverted from the rest of the engine. The
  others print or deliver; this one destroys pending state, so the safe
  direction has to be what you get by forgetting a flag.
- Closing goes through coord-done.sh --repo, never mv, so the archive
  layout and the _broadcast refusal stay in one place.
- Age is read from the filename prefix, never the file. An unreadable
  age is never treated as old: fail-safe, not fail-open.
- Every closure is logged with sender and subject. Directed messages
  have no seen-tracking, so the sweep cannot tell "seen and ignored"
  from "never delivered" -- a notice can be closed unread, and the log
  is the only thing standing between that and silent data loss.

The reply-expected read is bounded to the frontmatter block, matching
coord-count.sh: a body line claiming it at column 0 is untrusted
cross-repo input and must not close its own message.

No scheduler, no launchd unit, no skill front door -- the script does
nothing until invoked.

Selftest 159 -> 182. The log check caught a real defect during
development: the first implementation read from/subject AFTER
coord-done.sh had moved the file, logging empty values and quietly
defeating the only safeguard the design has.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Uwcak9j4m9JijDKeFmptww

CHANGELOG.md

@@ -5,6 +5,58 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.14.0] - 2026-08-01
+
+### Added
+
+- **`scripts/coord-sweep.sh` — the FYI backlog closes itself, deterministically
+  and without a model.** A notice needs no answer, but it is still re-injected at
+  every session start until someone closes it by hand. Across enough
+  repositories that hand-closing *is* the manual work the mailbox was supposed to
+  remove, and the pending count — the operator's only signal — drowns in messages
+  that were never going to be acted on. At the time of writing, 9 of 22 pending
+  messages across 12 mailboxes were pure notices.
+
+  The sweep closes exactly one mechanically decidable class: a directed message
+  whose sender declared `reply-expected: no`, older than a grace window (default
+  14 days, `--days`). **A message that owes a reply is never touched, at any age,
+  with any flag** — answering it would mean deciding something on the receiving
+  repo's behalf, which is the one thing this system exists to prevent a session
+  from doing.
+
+  Four properties are load-bearing rather than incidental:
+
+  - **Dry-run is the default**, inverted from every other script here. The others
+    print or deliver; this one destroys pending state, so the safe direction has
+    to be the one you get by forgetting a flag.
+  - **Closing goes through `coord-done.sh --repo`, never `mv`.** The engine owns
+    the filename grammar and the archive layout, and it already refuses
+    `_broadcast` on its own — archiving out of there would retire an announcement
+    for every repo that has not read it yet, an unauthenticated retract.
+  - **Age is read from the filename prefix, never from the file.** A name the
+    grammar does not produce has no readable age, and an unreadable age is never
+    treated as old: fail-safe, not fail-open.
+  - **Every closure is logged** (`$CLAUDE_COORD_DIR/_sweep.log` by default) with
+    sender and subject. This is not bookkeeping. A directed message has no
+    seen-tracking — only broadcasts do — so the sweep cannot distinguish "seen and
+    ignored" from "never delivered", and a notice to a repo left unopened for the
+    whole window is closed **unread**. That is an accepted tradeoff; the log is
+    the only thing standing between it and a silent disappearance.
+
+  The `reply-expected` read is bounded to the frontmatter block, matching
+  `coord-count.sh`: a body line claiming `reply-expected: no` at column 0 is
+  untrusted cross-repo input and must not be able to close its own message. That
+  is the one place where getting it wrong would let another repo delete its way
+  out of your inbox.
+
+  Scoped deliberately: no scheduler, no launchd unit, no skill front door. The
+  script does nothing until invoked.
+
+- Selftest 159 → 182 checks (new section 29). The log check caught a real defect
+  during development — the first implementation read `from`/`subject` *after*
+  `coord-done.sh` had already moved the file, logging empty values and quietly
+  defeating the only safeguard the design has.
+
 ## [0.13.0] - 2026-07-31
 
 ### Added