re: sweep the SILENT instruction surface -- 5 files still named a dead gate

sylpheed-port refined my ranking: rank silent instructions above loud ones. All
of theirs were loud -- wrong paths that error out and announce themselves --
while mine was silent: an inert env var returning a clean, wrong result. Only the
silent kind manufactures evidence.

The silent surface is enumerable, so this is a sweep rather than a sample: every
environment variable the docs name, checked against the code.

SYLPHEED_KF_TIME_SHIFT was still live in FIVE doc files after I fixed one last
iteration. Two of the five were genuine hits rather than historical quotes:

  ui-resting-pose.md -- a RESULTS TABLE ROW labelled "with
  SYLPHEED_KF_TIME_SHIFT=1". Re-running it sets an inert variable, produces the
  DEFAULT row, and lets a reader conclude the two readings agree. A stale
  instruction inside a results table is the purest form of the evidence-
  manufacturing class.

  HANDOFF.md -- "experiment reachable via SYLPHEED_KF_TIME_SHIFT=1", a live
  instruction in the delivery contract.

And a live gate exists under a DIFFERENT NAME that the docs never pointed at:
SYLPHEED_KF_TIME_LEGACY, verified read at ui_layout.rs:595 -- the parser itself,
not only the tests, so it does reach screen info and screen render. Both hits now
redirect there.

Beware the proxy, which is the trap the port named about their own "parsed"
check: absent-from-code also flags SYLPHEED_DISC, XENIA_SRC and SYLPH_ISO, which
are container paths the brief sets and no code reads. Absent-from-code is
necessary, not sufficient, and I checked each rather than reporting the seven raw
hits.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Wuu56cE8vJGTBtn1ppsk8v

docs/port/HANDOFF.md

@@ -1996,7 +1996,12 @@ discovered it after re-exporting. ❔ The sweeps may simply be a small term, and
   this element to the visibly wrong answer, so it and a decision about
   plateau-less elements have to land together, and neither half has a capture to
   verify against.
-  **Default unchanged**, experiment reachable via `SYLPHEED_KF_TIME_SHIFT=1`.
+  **Default unchanged**, experiment reachable via `SYLPHEED_KF_TIME_LEGACY=1`.
+  ⚠️ **This line said `SYLPHEED_KF_TIME_SHIFT=1` until 2026-08-30** — a variable
+  removed with the record-layout fix. Setting it does nothing and yields the
+  default, so the instruction would have produced a clean, wrong confirmation
+  rather than an error. `SYLPHEED_KF_TIME_LEGACY=1` is the live gate
+  (`ui_layout.rs:595`).
   **What this means for you:** the interpolation *law* is settled (linear, 2
   units/frame); a multi-keyframe group's *timing* is not — do not expect a
   2-frame hold where the game holds 83.

docs/re/structures/ui-resting-pose.md

@@ -609,7 +609,7 @@ end of that movement the indexing lands on:
 | | returned "rest pose" |
 |---|---|
 | as decoded | `(108,72) 0%,0% a=0` — invisible |
-| with `SYLPHEED_KF_TIME_SHIFT=1` | `(108,72) 200%,200% a=255` — the peak |
+| with `SYLPHEED_KF_TIME_LEGACY=1` ⚠️ | `(108,72) 200%,200% a=255` — the peak |
 
 An 896×389 sprite at 200 % scale is 1792×778 — larger than the screen. Painting
 it permanently is what made build 7's render 13.1 % different and 4.9 luminance
@@ -1189,3 +1189,12 @@ rests.
 keyframe timing now supports ([time unit](../ui-keyframe-time-unit.md)). Use a
 static composite for the title, main menu and `EXTRAS`, where the screen does
 settle and `rest_plateau` is measurably right.
+
+
+⚠️ **The row above said `SYLPHEED_KF_TIME_SHIFT=1` until 2026-08-30.** That gate
+was removed with the record-layout fix and reading it back would have set an inert
+variable, produced the DEFAULT row, and let a reader conclude the two readings
+agree — a stale instruction inside a results table, which is the form that
+manufactures evidence rather than merely misleading. The live equivalent is
+`SYLPHEED_KF_TIME_LEGACY=1`, read in `ui_layout.rs:595` (the parser itself, not
+only the tests, so it does reach `screen info` and `screen render`).