CB-WP-0015: the two inert clauses, AM-7 scaling and AM-8 N=10

Provenance (tier S, one paragraph in lieu of survey and ADR): the two
clauses mutation-check has reported inert since CB-WP-0005. AM-7's
scaling ratio was held up by a test literally named
replay_100k_events_is_linear_and_fast that computed both throughputs,
printed both, and never divided one by the other. AM-8's N=10 was held
up by a runner that does two.

Both are now red. AM-7 3/3, AM-8 2/2, M-D1-MUT 10/14, and ADR-0005's
>=10-of-14 prediction MET for the first time. Neither was closed by
amending the question away, which was the live risk: the denominator is
unchanged and the four unenforced rows are the four already
unenforceable.

AM-7 needed three estimators. Best-of-N per leg then divide (AM-6's,
correct for a floor on one number) gave 0.581-1.085 on an unchanged
binary; legs back-to-back gave medians 0.931-1.004; legs interleaved at
fold granularity give 0.987/0.991/0.989, and 0.989 under 8-way CPU
contention while absolute throughput fell 4x. The INDETERMINATE guard
demanded unanimity and failed a good measurement over one sample
0.001 under the floor; it now requires a two-thirds majority. The
control that matters: AM-6's constant-cost mutation halves throughput
and leaves this ratio at 0.999x green, so AM-7 is not a second AM-6.

AM-8 kept N=10 because the measurement said so. Perturbing the RNG only
from its fourth construction on: --runs 2 PASSES, --runs 10 fails. A
late-onset divergence is deterministic, not flaky, so it is a control
rather than a coin flip. Ten runs live on one scenario (make am8, ~2s)
rather than all 25 (47s a build). GameKernel 5b records it.

The full run also found AM-4a's own mutation stale since ADR-0008 D3
moved the target 250,000 -> 161,000 in CB-WP-0013 -- reported
HARNESS-BROKEN, no score published. The build-free half of that check
is now a --self-test assertion, so make all catches the next one.

mutation-check clauses may now carry their own verify and mutation, and
then the enforced flag is measured rather than declared; a declaration
disagreeing with its measurement is refused.

make all exits 0.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

gates.toml

@@ -19,7 +19,7 @@
 # `loop-lint` fails when a target is in neither list.
 not_control_gates = [
   "check", "test", "sim", "bench-test", "size-metrics", "runtime-metrics",
-  "am6", "replay-test", "dep-weight", "self-tests", "env-test",
+  "am6", "am7", "am8", "replay-test", "dep-weight", "self-tests", "env-test",
 ]
 
 [[gate]]
@@ -62,6 +62,8 @@ caught = [
   "K10's first round trip not reproducing",
   "the bench workload existing twice",
   "AM-2's expect matching its own passing output (EXPECT-VACUOUS)",
+  "CB-WP-0015: the two clauses it had reported inert since CB-WP-0005 — AM-7's scaling ratio (a test named `replay_100k_events_is_linear_and_fast` that computed both throughputs, printed both, and never divided one by the other) and AM-8's N=10 (the runner did two). Both now red, 10/14, and the >=10-of-14 prediction met for the first time",
+  "CB-WP-0015: AM-4a's own mutation, stale since ADR-0008 D3 moved the target 250,000 -> 161,000 in CB-WP-0013. Reported HARNESS-BROKEN and refused to publish a score, which is the harness catching itself. The build-free half of that check is now a --self-test assertion, so it runs in `make all` instead of only on a full run",
 ]
 retire_if = "a full pass adds rows without finding anything, twice running — the harness costs real money per run"