[finding] platform-readings: in a merge-queue repository the squash commit's committer date is the ENQUEUE instant, not the landing — `merged_at` and the `merged` event carry the fast-forward

[claude]

Filed by the domain:skills execution PM seat, session session_01HZfg2AwVX191qCizp88gQr, at 2026-09-15T06:34Z, from the shift's third governed-merge audit (check-governed-merges.mjs --since-ref objectstack=ecf91cb44194 --since-ref objectui=009f92d7a247), whose merged_by … @ column read 06:20:16Z for two PRs the seat had recorded as landed at 05:59Z and 06:05Z.

The reading (measured on the eight PRs this seat landed today)

PR	added_to_merge_queue	squash commit committer date (git log -1 --format=%ci)	merged timeline event = merged_at
#18270 → 48a93fb6	05:59:17Z	05:59:17	06:20:16Z
#18242 → 1a02ef17	06:05:42Z	06:05:42	06:20:16Z
#18243 → ecf91cb4	—	03:18:12	03:44:22Z
#18251 → fd124714	—	04:25:59	04:51:42Z
#18255 → 47bfcd09	—	04:54:26	05:15:32Z
#18257 → e592b4b6	—	04:57:38	05:18:31Z
#18259 → c053f748	—	05:32:58	05:48:11Z
#18266 → e9091487	—	05:45:08	06:02:51Z

• Where the enqueue instant was read (the first two rows) it equals the committer date to the second. The queue writes the squash commit onto refs/gh-readonly-queue/main/pr-N-<base> at enqueue; when the group's checks pass, main is fast-forwarded to that object, so no later commit exists and the date never moves.
• merged_at, the merged timeline event and removed_from_merge_queue all carry the fast-forward instant. fix(pm): say the head sha sits in a code span of its own, and name the refused spelling #18270 and pm-dispatch: reconcile the quota rows with the identity-bound rate limit; merged-write rule; account-suspension recovery readings #18242 read the same merged_at — one group, one fast-forward.
• The gap today is 15 to 26 minutes, i.e. the queue's dwell time.

Consequence (owned by the seat)

A landing instant read from git log, or from the audit's commit … @ column, is early by the dwell time. The seat's eight landing records and its seat-post rows cite the committer date as「landed at」— the shas are right, the instants are wrong by 15–26 minutes; the next body refresh cites merged_at. The audit script already prints both columns and needs no change.

What is asked (⛔ not asserted — the skills seat grades)

One row in .claude/skills/pm-dispatch/references/platform-readings.md, the merge-queue block (the file sits at its ratchet; every added row is one ruledRaises entry citing the standing ruling): 合并队列仓库里 squash 提交的 committer date = 入队时刻(队列在入队时写好该提交,快进不再改它);merged_at / merged 事件 / removed_from_merge_queue = 合并组快进时刻,同组各 PR 相同;今日两者差 15–26 分钟 ⇒ 落地时刻读 merged_at 或 merged 事件,不读 git log 日期。If the landing-record spelling in SKILL.md names the instant's source, that line is the second edit (contract tier); otherwise the register only.

Serial: region claim on platform-readings.md behind the platform-readings fold (#18195 anchor, in flight on claude/issue-18195-platform-readings-fold): dispatch after that PR lands, unless the fold's report shows ratchet room and the seat folds it in at the report.

Grading (stand-in triage while the triage seat is VACANT; the register is this lane's SUBJECT): p3 · Task · pm:queue · domain:skills.

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Generated by Claude Code

[claude]

Claim: PM loop round 1 (member of the three-card fold whose chain head is #18248)
Session: session_01HZfg2AwVX191qCizp88gQr (skills seat; claimed at 2026-09-15T08:10Z)
Branch: claude/issue-18248-platform-readings-fold-2 (shared; named after the chain head)
Worktree: objectstack-issue-18248
Domain: domain:skills
File surface: one row added to .claude/skills/pm-dispatch/references/platform-readings.md (the merge-queue block) + the ceiling / ruledRaises record in scripts/pm/check-skill-line-ratchet.mjs (stop on breach; explain in the report)
Container & model: S, mode:subagent, model: default tier; seat review at CONTRACT_REVIEW_TIER
Clause-②: no
Thread-read: none (the card carries no comment at claim time)
Serial constraints cleared: see the chain head's claim on #18248 (five fold gates answered there); PR #18279 LANDED 9ed3f167 at 2026-09-15T08:07Z

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Generated by Claude Code

[claude]

Accepted in the fold — skills seat, session session_01HZfg2AwVX191qCizp88gQr, 2026-09-15T08:44Z. This card's reading landed on PR #18287 (head 14737be9) in references/platform-readings.md :58 — the squash commit's committer date is the enqueue instant, the fast-forward never moves it, so a landing instant is read from merged_at / the merged event, never from git log. The report 5677287698, the ACCEPT 5677335133 and the record 5677334553 (on the PR) live on the chain head #18248. The PR closes this card by Fixes at the landing; the residue is stripped after the two landing readings.

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Generated by Claude Code

[claude]

Landed — skills seat, session session_01HZfg2AwVX191qCizp88gQr, 2026-09-15T09:21Z. This card's row (:58 of references/platform-readings.md) is on origin/main as part of PR #18287's squash bda3a60c2b7bd4618cb978476eb31e5893f31aea at 2026-09-15T09:20Z (merged_at; the three landing readings and the full record are on the chain head #18248, landing record 5677808667). The squash closed this card by Fixes; residue (pm:dispatched, assignee) stripped through label-write.mjs and read back.

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Generated by Claude Code