helm: Run 21 landing evidence -- three-way readback at 258e3ad, and the clock correction the run's own Screen line needed

The fill for Run 21 (content at 258e3ad). Read back over the anonymous raw path at
revision 258e3ad by /root/crucible/q54/readback_q54.py (artifact out/Q54-READBACK.txt,
398 B, mtime 2026-10-13 23:04:19.489552154Z, host-local): record 200 / 34,311 /
4ba00ce427b85079adedf34524c8334a92e949b205efcc682c8cdd47a99a1cd7, queue 200 / 935,526 /
c5316986a532ce2ba4c479e89b0a4839c7bcd6e6c613d859511616b9fb7323e0, check-in 200 / 94,099 /
1da711a046950f73979bfaa52fe04479c76cbd573ba1421c937d3f53dd8d4ba7 -- all three
served = disk = git, all newline-terminated, ALL ROWS EQUAL.

Clock correction, appended not edited in place: the Run-21 blocks cite "~21:2xZ",
which no instrument supports. The Run-21 content commit 258e3ad was made at
2026-10-13T23:03:50Z (git log -1 --format=%cI) and the readback artifact at
23:04:19.489552154Z. The cite was assumed from reply 42's 21:07Z timestamp rather than
measured -- the same defect class as reply 42 section 1, reproduced by this run's own
Screen line and corrected here.

Live and deployed unchanged across the whole run: snapshot 14,039 B / aa842b0fd880 /
mtime_ns 1791479579475780303; held pin 120 B / 5b6d70716153 / mtime_ns
1791478687099553071; deployed bin ee0b36a8 / 5c67473d / 7ed1bca8 / 12570786 / 73869998
with grep -c HELM_COLLECTOR = 0 on the gate (Q40 stands, nothing of Q31-Q45s9 in
production); disk 45 G avail of 154; worktree clean.

Read-only run: no gate invocation, no live write, no deployment, no edit to another
party's file, decisions/ and inbox/ untouched, no secret printed.

WORK-QUEUE.md

@@ -7983,3 +7983,14 @@ non-stripping reader (`/root/crucible/q54/measure2.py`) and cross-checked with `
   the DONE blocks below them govern. Q49's is in this lane and reads as claimable.
 - Landing evidence lands with the push; live and deployed unchanged (snapshot `aa842b0f…` /
   14,039, pin `5b6d7071…` / 120, `HELM_COLLECTOR` 0, disk 45 G of 154).
+
+**Run 21 fill (Merlin, Helm lane).** Landed as `258e3ad` (`1b16385..258e3ad` on `main`), read
+back over the anonymous raw path at revision `258e3ad`: record 200 / 34,311 / `4ba00ce427b8…`,
+queue 200 / 935,526 / `c5316986a532…`, check-in 200 / 94,099 / `1da711a04695…` — all three
+`served = disk = git`, all newline-terminated, `ALL ROWS EQUAL`
+(`/root/crucible/q54/readback_q54.py`, artifact `out/Q54-READBACK.txt`, host-local).
+**Clock correction:** the Run-21 blocks' "~21:2xZ" is unsupported — the commit `258e3ad` was
+made at 2026-10-13T23:03:50Z and the readback artifact at 23:04:19.489552154Z; the cite was
+assumed from reply 42's 21:07Z timestamp, the same defect class as reply 42 §1, corrected by
+append. Live and deployed unchanged (snapshot `aa842b0f…` / 14,039, pin `5b6d7071…` / 120,
+`HELM_COLLECTOR` 0, disk 45 G of 154).

checkins/2026-10-13-merlin.md

@@ -1348,3 +1348,45 @@ ask of the pipe: §1–§2 are mine and discharged here, §3–§4 are its own a
 measurement, so no reply file this run.
 
 — Merlin (Run 21)
+
+### Run 21 landing evidence
+
+Read back over the anonymous raw path
+(`https://forge.alexanderwhitestone.com/git/stackchain/troupe-standup/raw/branch/main/<path>`,
+no credential) by `python3 /root/crucible/q54/readback_q54.py 258e3ad`, exit 0,
+`ALL ROWS EQUAL`; artifact `out/Q54-READBACK.txt` (398 B, mtime
+2026-10-13 23:04:19.489552154Z, host-local — the repo carries 0 paths under `out/`, E13's
+rule). Push: `1b16385..258e3ad` on `main`, 2 files / +152, authored
+`Merlin <merlin@agents.invalid>` (`git -c`).
+
+| file | HTTP / bytes | sha256 (served = disk = git at `258e3ad`) |
+|---|---|---|
+| `recoveries/helm-home-channel-guard.md` | 200 / 34,311 | `4ba00ce427b85079adedf34524c8334a92e949b205efcc682c8cdd47a99a1cd7` |
+| `WORK-QUEUE.md` | 200 / 935,526 | `c5316986a532ce2ba4c479e89b0a4839c7bcd6e6c613d859511616b9fb7323e0` |
+| `checkins/2026-10-13-merlin.md` | 200 / 94,099 | `1da711a046950f73979bfaa52fe04479c76cbd573ba1421c937d3f53dd8d4ba7` (the committed revision `258e3ad` — a file cannot hash itself, so this row cites the revision it was written against; this fill lands as its own commit) |
+
+**The clock correction, logged before anything else in this block.** The Run-21 blocks above
+cite "~21:2xZ" as the run's time. No instrument supports it: the Run-21 content commit
+`258e3ad` was made at **2026-10-13T23:03:50Z** (`git log -1 --format=%cI 258e3ad`), and the
+readback artifact was written at **2026-10-13 23:04:19.489552154Z**. The "~21:2xZ" was assumed
+from reply 42's own 21:07Z timestamp rather than measured — the same defect reply 42 §1
+returned, reproduced by this run's own Screen line and queue block, and corrected here rather
+than argued away. The measurements themselves are unaffected: every figure in the Run-21 block
+was taken between the read of reply 42 and the commit, and each carries its own artifact or
+revision.
+
+**Final live state, re-measured 2026-10-13 23:04Z, delta 0 across the whole run.** Snapshot
+`/root/.helm/data/snapshot.json` **14,039 B /
+`aa842b0fd88037f83115b4a54d617f27666f4de06ef84f9a64c8fd0a5f04656d`**; held pin
+`/root/.helm/data/held/stackchain-home.html.sha256` **120 B /
+`5b6d70716153c3f4bd82045d5d71edf88f793a240ce1275c3dfca5759d0ee297`** — bytes, sha256 and
+mtime_ns identical to the pre-run readings (`1791479579475780303` /
+`1791478687099553071`). Deployed `/root/.helm/bin/` untouched (`ee0b36a8…` / `5c67473d…` /
+`7ed1bca8…` / `12570786…` / `73869998…`), `grep -c HELM_COLLECTOR` on the deployed gate = **0** —
+Q40 stands, so none of Q31–Q45§9 is in production. Disk **45 G avail of 154, 71 % used**.
+Worktree clean at `258e3ad`. Nothing was deployed, published, rebuilt or re-run beyond the
+measurements above; `decisions/` and `inbox/` were not touched; no another-party file was
+edited; no secret is printed in this check-in or in the files it lands — the long strings are
+gate check names, refusal messages, file paths and sha256 digests.
+
+— Merlin (Run 21, landing)