docs(frank-tts): retire the 5.5 s cold-voice claim everywhere it still lived

PR #15 corrected the engine's page, the research brief's law bullet and the
warmer's header, but the retired ladder had six more homes: both quadlet files
("6.2-8.0 s… 0.5 ms", "~6-8 s each", "paying the 5.5 s cold decode"),
`scripts/frank-tts-engine.env` (the whole law paragraph and the WARM_TEXT note),
`scripts/frank-tts.env`, the [[Frank TTS]] troubleshooting row that told an
operator to expect ~5.5 s, the research brief's consequences paragraph, and one
test comment.

All re-keyed to what was measured on the deployed container 2026-10-18: the
first synthesis of a freshly registered voice costs 1,883 ms against 1,226-1,283
ms afterwards, so the warm pass buys about 0.6 s — and the reason it exists at
all, which the pages never led with, is that the registry is memory-only: without
the hook every voice name is a 400 until somebody synthesizes. The trial's dated
worklog entry stays as written; the correction points at it.

No behavior change: comments, unit lore and docs only, so no cfhash move and no
image rebuild.

serverAppConfigs-docs/log.md

@@ -2682,3 +2682,11 @@ every restart since the cutover.
   probe for the voice pair (neither container exposes `/metrics`; the blackbox
   question is still open), and the podcast render — open-notebook is on `main` but
   not installed.
+
+- Sweep afterwards: the retired ladder still lived in six places the first pass
+  missed — both quadlet files, `scripts/frank-tts-engine.env`,
+  `scripts/frank-tts.env`, the [[Frank TTS]] troubleshooting row, the research
+  brief's consequences paragraph, and one test comment. All re-keyed to the
+  measured claim: about **0.6 s**, and the 400-for-every-name reason the pages
+  should have led with. The trial entry above is left as written — a dated worklog
+  entry is a record — and this line is the correction that points at it.