port: test the half-guard they named -- it found a real gap on first use

They flagged that my pose line reports the pins from the variables in force,
never checked against a pin set but not reaching the view. I had recorded the same
doubt and not acted on it.

The case is the overlay: a second ScreenView with its own pins, while the
announcement read view.* only -- and the plate carries a looping focus record,
the clock in question, drawing from overlay.*.

Extended the line to report the overlay's pins, and its first use printed
overlay(loop-phase=0.0, leaf=free): overlay.loop_phase_units was wired and
overlay.leaf_time_units was not. A run requesting both had one pin reach the
overlay and one not, and the pre-fix announcement would have printed leaf=0.0 from
the main view while the overlay drew free-running. Their half-guard precisely.

Currently inert -- press_start carries no leaf, so the render is byte-identical
before and after. The gap was real, live for any overlay carrying a leaf, and cost
nothing today.

Fourth instance of their remedy of putting the qualifier in the text rather than
the reader's memory, and it caught something within a minute of existing.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01N7FiFFFwbvG2uxdcEh8HyF

docs/port/DECISIONS.md

@@ -9,7 +9,7 @@ dies, which is what this file is for.
 
 <!-- INDEX: generated by tools/port/index-decisions -- do not hand-edit -->
 
-218 sections. Search this before re-deriving anything.
+219 sections. Search this before re-deriving anything.
 
 * [P0 — the exporter, 2026-08-28](#p0--the-exporter-2026-08-28)
 * [P1 — Godot draws the screen, 2026-08-28](#p1--godot-draws-the-screen-2026-08-28)
@@ -229,6 +229,7 @@ dies, which is what this file is for.
 * [Branches that announce themselves — their lesson, applied where it already bit me](#branches-that-announce-themselves--their-lesson-applied-where-it-already-bit-me)
 * [Every documented invocation verified — and one runs forever without saying so](#every-documented-invocation-verified--and-one-runs-forever-without-saying-so)
 * [🔴 I promoted an unverified claim of theirs to a fact, against data I had authored](#i-promoted-an-unverified-claim-of-theirs-to-a-fact-against-data-i-had-authored)
+* [The half-guard they named, tested — and it found a real gap on first use](#the-half-guard-they-named-tested--and-it-found-a-real-gap-on-first-use)
 
 <!-- /INDEX -->
 ## P0 — the exporter, 2026-08-28
@@ -11512,3 +11513,46 @@ Same kind of destination, different gap, so the destination is not the variable.
 ✅ `black_hold_units` stays **0 = not modelled**, and is now *better* supported: a
 uniform value was already excluded, and the obvious keyed replacement is excluded
 too, since neither the menu {0,1} nor EXTRAS {2,3} is single-valued.
+
+## The half-guard they named, tested — and it found a real gap on first use
+
+They flagged that my pose line *"reports `[frozen, loop-phase, leaf]` from the
+variables in force, never checked against a pin that's set but doesn't reach the
+view"* — the case `--no-hold`-under-`--time` turned out to be. I had recorded the
+same doubt and not acted on it.
+
+**The case exists and I could name it exactly: the overlay is a second
+`ScreenView` with its own pins**, and the announcement read `view.*` only. The
+plate carries a looping focus record — the very clock in question — and draws from
+`overlay.*`.
+
+✅ Extended the line to report the overlay's pins. 🔴 **Its first use found a real
+gap:**
+
+```
+[frozen, loop-phase=0.0, leaf=0.0, overlay(loop-phase=0.0, leaf=free)]
+```
+
+**`overlay.loop_phase_units` was wired; `overlay.leaf_time_units` was not.** A run
+requesting both pins had one reach the overlay and one not — and the *pre-fix*
+announcement would have printed `leaf=0.0` from the main view while the overlay
+drew free-running. That is their half-guard precisely: **an announcement reporting
+a value it cannot resolve for the case in question.**
+
+⚠️ **Currently inert, and worth saying so rather than claiming a save.**
+`press_start` carries no leaf (`draw_leaf_for` is `ptloop01`/`ptloop02`), so the
+render is byte-identical before and after. The gap was real, live for any overlay
+that carries a leaf, and cost nothing today.
+
+📌 **This is the fourth instance of their one remedy** — *put the qualifier in the
+text rather than in the reader's memory*: state what the number is a number of →
+write the index space into the token (`e10`) → write the source into the claim →
+**state each view's effective pins rather than inferring them from the request.**
+Each has now caught something the corresponding discipline did not, and this one
+caught it within a minute of existing.
+
+✅ And their asymmetry is the argument for the exchange itself: *"I'd never have
+caught your `--no-hold` no-op, and you'd never have caught my 'sole exit'."*
+Neither of us is the right auditor of our own retiring words. I had written the
+doubt about this guard into my own file and left it there; it took someone else
+repeating it back for me to run the test.