fix(retrieval): the review drops records written after the call it re-runs (#4773)

The first live sample ranked records the call could never have been offered:
the session that made a call writes the decision, often quoting the message,
and that record tops the re-run. Judged, it inflates on_point exactly where
the budget is decided.

- _rerun over-fetches by POSTDATED_SLACK, drops records created after the
  call before ranking, and names them in `postdated`.
- each line carries `changed_since_call` (updated_at or a work log after
  the call) and `logged` (shown fresh then).
- judge_menu shares the re-run, so a post-dated record cannot be judged.

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

src/scribe/mcp/tools/retrieval_review.py

@@ -29,6 +29,13 @@ async def menus_to_review(
     `missing` names ids the call logged that the re-run no longer finds — the
     corpus has moved since. Judge what is in front of you.
 
+    The re-run is against today's corpus, so it guards what has been written
+    since. Records created after the call are left out and named in
+    `postdated`: the call could not have offered them, and the session that
+    made it often wrote them, quoting it. A line marked `changed_since_call`
+    was written to afterwards; if its passage is plainly the later text, leave
+    it unjudged. `logged` says the line was shown fresh at the time.
+
     JUDGE FROM THE LINE; DO NOT OPEN THE RECORD. Opening counts as a pull and
     would credit the arm with an open it never earned. Then record verdicts
     with `judge_menu`. `how_to_judge` in the response repeats the vocabulary.