docs(d4): correct the gap to 38m25s — the two timestamps came from different clocks

The 2199 seconds reported for D-4 subtracted a test-server timestamp
(archive/cert2.pem mtime) from a dev-machine timestamp (the serial change
observed by the poll), without noting they are different clocks.

Checked against external references: the dev machine matches Google and the
Let's Encrypt ACME endpoint to the second, while test-server is 105 seconds
fast and reports NTPSynchronized=no. Three round-trip measurements put the
offset at +106.1s every time.

Corrected:

  new certificate written to disk  08:20:27 UTC   (mtime 17:22:13 KST - 106s)
  actually served                  08:58:52 UTC   (dev observation, no correction)
  gap                              2305s = 38m25s

The correction validates itself in D-4a, where the new certificate's SCT —
signed by CT logs on their own accurate clock at 12:27:49.054 GMT — lands
one second before the skew-corrected hook time. Without the correction the
hook would appear to have run 104 seconds before the certificate existed.

Updated across the experiment doc, the index, the follow-up doc, the verdict
evidence file and the SVG.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docs/diagrams/d4-renewal-gap.svg

@@ -17,7 +17,7 @@
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-<text x="20" y="26" class="ttl">D-4 — 「갱신 성공」과 「새 인증서 서빙」 사이의 36분 39초</text>
+<text x="20" y="26" class="ttl">D-4 — 「갱신 성공」과 「새 인증서 서빙」 사이의 38분 25초</text>
 <text x="20" y="44" class="s">측정: 2026-09-04 · 일련번호 5초 간격 564표본 · 새 연결 0.2초 간격 8856건</text>
 
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@@ -81,7 +81,7 @@
 <text x="730" y="342" class="s" text-anchor="middle" fill="#1a7f37">06C7CB…EA1D</text>
 <path d="M300 416 L660 416" class="r" marker-end="url(#ar)"/>
 <path d="M660 416 L300 416" class="r" marker-end="url(#ar)"/>
-<text x="480" y="410" class="tb" text-anchor="middle" fill="#cf222e">36분 39초</text>
+<text x="480" y="410" class="tb" text-anchor="middle" fill="#cf222e">38분 25초</text>
 <text x="480" y="434" class="s" text-anchor="middle">사람이 reload 했기에 36분이다. 아무도 안 했다면 다음 재시작까지 — 무기한</text>
 
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