feat(pm): H61 reports a merged PR or closed card still carrying needs:contract-review

The half-state patrol could see a contract-review gate on an OPEN carrier
(H31, H51, H53) and a gate REMOVAL (H35). It could see nothing at the other
end: a pull request that MERGED, or a card that CLOSED, with the label still
on it. 载体纪律's invariant is 「开着的载体恒 = 真实待审」, so each of those
labels still tells a later reader that a real contract review is owed on work
already in `main`.

H61 is one report-only row per landed carrier, printing the merge or closure
stamp and the PR's head sha. It costs no request: merged PRs come from H8's
8-day window and closed cards from H22's 3-day window, whose list rows already
carry `labels`, `merged_at` / `closed_at` and `head.sha`. Closed-UNMERGED PRs
are excluded by decision (measured: 2 of 68 carriers) and both legs pin the
refusal. Exit codes, bands and every other row are unchanged, and the script
still never writes a label.

Co-authored-by: Claude <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MCLBsUgfykL74aU716rzVK

Author: claude