docs(frank-tts): the cold-voice ladder did not survive the deployment

The first real boot gave the chance to measure what warming actually buys, and
the trial's numbers were wrong:

- Empty registry, register only, then time: the FIRST synthesis of a freshly
  registered voice cost 1 883 ms; the next two 1 283 and 1 226 ms. A ~110-word
  request cost 9.4 s and then 9.8 s.
- So the published 6.2–8.0 s cold / first-audio-byte 5 530 ms / later-requests
  0.5 ms ladder does not reproduce, and request time tracks the audio generated
  rather than snapshot state. The 0.5 ms figure is an internal state-restore
  cost, never an end-to-end request time.
- Warming still earns its place for a different reason than the page claimed:
  the registry is memory-only and re-registering does not warm, so a boot without
  the hook leaves the façade answering 400 for every name. The saving is ~0.6 s.

Law 1 of [[Frank TTS Engine]] is re-titled the registry law and carries the
measured numbers; its example journal line is a real one from today; the
troubleshooting row for "first request of the day is slow" — the retired law's
symptom — is replaced by the argument-cap fault that actually happened. The same
ladder in the research brief is annotated rather than erased, and [[Voice Packs]]
step 6 stops claiming the hook registers only packs it has not seen (the engine
replaces a name it already holds).

serverAppConfigs-docs/Dankclaw/Voice Packs.md

@@ -169,10 +169,14 @@ invariant to every crop in the tracked pack list.
    curl -s localhost:7772/v1/audio/voices      # the façade's list, not the engine's
    ```
 
-   The hook walks `/voices`, registers any pack with a `reference.wav` it has not
-   seen, and logs `voice <name> cold=…ms warm=…ms` to the unit's journal. The
-   rootless unit restart — `systemctl --user restart frank-tts-engine.service` —
-   is for when the unit or its env changed, not for a new pack.
+   The hook walks `/voices` and registers **every** pack that has a
+   `reference.wav`, on every run — the engine replaces a name it already holds
+   (`tools/tts-server.cpp:148` at the pinned commit: *"Re-registering a name
+   replaces the previous entry."*) — then synthesizes twice per voice and logs
+   `voice <name> cold=…ms warm=…ms` to the unit's journal. The two numbers should
+   be close; see law 1 of [[Frank TTS Engine]] for what they measure. The rootless
+   unit restart — `systemctl --user restart frank-tts-engine.service` — is for when
+   the unit or its env changed, not for a new pack.
 
 ## When the extractor's output size changes on an engine bump