memory: no fleetwide notice for U4, and the measurement caveat it creates

Operator decision 2026-09-22: no broadcast to the 17 consuming handles. Same
posture as U5 — adoption gets told apart from design because nobody was primed.

The consequence is a measurement one and it needed writing down before it was
lost. U4's two halves have different adoption costs: the hold rides for free
(a session runs `booth ask` and its booth is held, knowing nothing), but NOT
pressing `keep` has to be learned. So a flat `.forever` rate on 2026-10-06 is
exactly what 'the mechanism works and nobody was told' looks like, and reading
it as a falsification would retire a correct diagnosis on an uncontrolled
measurement.

Records the three counts to report instead, and states the sensitivity floor:
only 4 of 24 booths carry marks at all, so the hold can touch at most a sixth
of the fleet and an effect below one or two booths is not resolvable.

persistent-memory.md

@@ -29,9 +29,11 @@ _As of 2026-09-22:_
   `c3a97c1` is the unit; the release commit carries the pre-existing fixes the
   bug-hunt panel surfaced in touched files. The tag waited for the last gate to
   close, per the `v0.2.0` lesson — see Tried and abandoned.
-- ⚠ **The 17 consuming handles have NOT been told** that `keep` no longer means
-  "waiting on an answer". That is the one coordination this release genuinely
-  warrants, and a fleetwide post needs operator approval before it is sent.
+- ⚠ **The 17 consuming handles are NOT being told** that `keep` no longer means
+  "waiting on an answer" — operator decision, 2026-09-22, no broadcast. This is
+  deliberate and it CHANGES HOW THE 2026-10-06 RE-COUNT READS: the hold rides
+  for free, but not-pressing-`keep` has to be learned, so a flat `.forever` rate
+  does not falsify anything. Read its entry before measuring.
 - **THE NEXT UNIT IS THE OPERATOR'S CALL.** U3 (declared embed seam) and U6
   (benches) are both unblocked; U7 waits on the rest. U6 is independent of
   everything and was conceptually unblocked by U5 giving job 5 a home; U3 is
@@ -64,6 +66,7 @@ _As of 2026-09-22:_
 
 - `[2026-09-22]` **U4 landed — lifetime is derived, not declared** — three states, viewing is activity, and no new arithmetic anywhere → `persistent-memory.d/2026-09-22-u4-derived-lifetime-landed.md`
 - `[2026-09-22]` **The `.forever` diagnosis got a live positive control** — 3 of the 4 booths awaiting an answer were ALSO hand-pinned — RE-COUNT 2026-10-06 → `persistent-memory.d/2026-09-22-forever-had-a-live-positive-control.md`
+- `[2026-09-22]` **No fleetwide notice for U4, and what that does to the prediction** — READ BEFORE THE 2026-10-06 RE-COUNT; a flat rate does not falsify the diagnosis → `persistent-memory.d/2026-09-22-no-notice-and-what-it-does-to-the-prediction.md`
 - `[2026-09-22]` **Four independent paths to one fail-open delete** — the bug-hunt panel's class, and the zsh word-splitting trap that shipped an empty bundle → `persistent-memory.d/2026-09-22-four-paths-to-one-fail-open-delete.md`
 - `[2026-09-22]` **Two reads of one file are not one read of one state** — a TOCTOU seam that composes two correct readers into a fail-open delete → `persistent-memory.d/2026-09-22-two-reads-are-not-one-state.md`
 - `[2026-09-22]` **Five of seven INV falsifiers did not falsify anything** — read before writing a *Falsifiable:* line; a green test cited one rather than being one → `persistent-memory.d/2026-09-22-vacuous-falsifiers.md`