docs: address Copilot review round 1

The 5000 arms of #2335's re-run each had exactly one red test — the
asyncUtilTimeout guard refusing the raised value — so "0 failures in
every arm" was a misstatement; both comments now say so. And the
AGENTS.md rule still gave the expiring-wait mechanism as the reason the
pin was measured worse, which the corrected record contradicts; it now
cites both measurements and keeps the mechanism as the hazard the rule
guards against.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PsmUAZ6aLUAFqenjJKSSRp
Signed-off-by: cliffhall <cliff@futurescale.com>

AGENTS.md

@@ -435,12 +435,16 @@ free to run a full `local:gate`). Raising a budget nobody chose hides no race.
   tool can be asked to resolve; assert at runtime when it is about behavior.
 - **A budget is stated, which is not the same as raised.** Testing Library's
   `asyncUtilTimeout` is pinned at its own default in both web setup files
-  because raising it was *measured worse*: a wait that is meant to expire —
-  a test asserting something never appears, a poll allowed to run out — spends
-  its whole budget on the happy path, so a raise is a proportional cost on
-  exactly those tests and starves the worker pool. Measure before raising a
-  budget that a passing test can spend in full; the call-site comment records
-  the three-arm run.
+  because raising it was *measured* and found to buy nothing: #2323's
+  three-arm run went red at 5000, and #2335's interleaved re-run on a leased
+  machine found no web test that lets a Testing Library wait expire on its
+  passing path and no difference between 1000 and 5000 beyond the guard
+  refusing the raised value. The hazard the rule guards against is still
+  real: a wait that is meant to expire — a test asserting something never
+  appears, a poll allowed to run out — spends its whole budget on the happy
+  path, so a raise is a proportional cost on exactly those tests. Measure
+  before raising a budget that a passing test can spend in full; the
+  call-site comment records both runs.
 - **An inner budget must be strictly smaller than the budget enclosing it.**
   `waitFor({ timeout: N })` inside a test whose own budget is `N` can never win:
   the test expires first and reports a timeout naming neither the wait nor its

clients/web/src/test/asyncUtilTimeout.test.ts

@@ -26,8 +26,9 @@ import { getConfig } from "@testing-library/react";
  * to expire spends the whole budget on the happy path, so a 5x raise is a 5x
  * cost on those tests — was checked on #2335 and does not hold here: no web
  * test lets a Testing Library wait expire on its passing path, and the same
- * three-arm protocol re-run interleaved on a leased machine showed 0 failures
- * in every arm and 0 tests at or above 5000ms with the raise in place. Raising
+ * three-arm protocol re-run interleaved on a leased machine showed no failure
+ * in any arm beyond this very assertion refusing the raised value, and 0 tests
+ * at or above 5000ms with the raise in place. Raising
  * the budget buys nothing, so the pin stays at the default until a measurement
  * says otherwise. `setup.ts` carries the full record.
  *

clients/web/src/test/setup.ts

@@ -31,8 +31,10 @@ import { cleanup, configure } from "@testing-library/react";
 // expiring-wait shape against Testing Library across the unit, `core/`,
 // integration and story files; no test at or above 2000ms in a full unit run;
 // and the same three-arm protocol re-run interleaved on a leased machine
-// (1000 / 5000 / reverted, three rounds) gave 0 failures in every arm and
-// 0 tests at or above 5000ms with the raise in place. Nothing on the passing
+// (1000 / 5000 / reverted, three rounds) gave 0 failures in every arm — the
+// one red test in each 5000 arm being `asyncUtilTimeout.test.ts` refusing the
+// raised value, which is the guard doing its job — and 0 tests at or above
+// 5000ms with the raise in place. Nothing on the passing
 // path spends this budget, so raising it buys nothing — and the #2323 reds
 // read as ambient load the arms did not share (an inference from that data,
 // not a re-measurement of the original run).