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>

Makefile

@@ -24,7 +24,7 @@ TOOLS := $(REPO)/tools
 # Every cargo recipe runs at the repo root; the shell does not persist cd.
 IN_REPO := cd $(REPO) &&
 
-.PHONY: check test sim bench bench-test coverage dep-weight cost cost-test cost-pin cost-budget shape-budget cost-mix loop-lint self-tests env-test task-done status facts-check facts-gen mutation-check size-metrics runtime-metrics build-time am6 replay-test loc play gate-review all
+.PHONY: check test sim bench bench-test coverage dep-weight cost cost-test cost-pin cost-budget shape-budget cost-mix loop-lint self-tests env-test task-done status facts-check facts-gen mutation-check size-metrics runtime-metrics build-time am6 am7 am8 replay-test loc play gate-review all
 
 ## fmt + clippy (deny warnings) + HashMap deny-lint
 check:
@@ -63,6 +63,23 @@ am6:
 	$(IN_REPO) $(CARGO) test --release -p games-ground --all-features \
 	  am6_throughput -- --ignored --nocapture --test-threads=1
 
+# AM-8 N=10 determinism gate. One scenario, ten same-seed replays, all
+# compared to the first. Not all 25: `make sim` already runs K8's double-
+# run over every scenario, and repeating that eight more times costs 47 s
+# per build to re-answer a question the second run already answered. The
+# extra runs exist for the probabilistic class, and one workload gives
+# that class its ten samples — see scenario::run_n.
+am8:
+	$(IN_REPO) $(CARGO) run -q -p cb-sim -- --runs 10 \
+	  $(REPO)/scenarios/ground/gr-r06-round-resolve.yaml
+
+# AM-7 scaling gate. Same release / single-thread reasoning as am6 and more
+# so: a *ratio* of two timings taken under varying contention is worse than
+# one reading, because the noise multiplies rather than cancels.
+am7:
+	$(IN_REPO) $(CARGO) test --release -p games-ground --all-features \
+	  am7_scaling -- --ignored --nocapture --test-threads=1
+
 # AM-9 peak RSS (fast, gated). AM-5 needs a clean build — see build-time.
 runtime-metrics:
 	$(PY) $(TOOLS)/runtime-metrics.py --fast
@@ -186,4 +203,4 @@ loc:
 		printf '%-28s %s\n' $$d "$$(find $$d/src -name '*.rs' | xargs cat | grep -vcE '^\s*(//|$$)')"; \
 	done
 
-all: check test sim coverage size-metrics runtime-metrics am6 replay-test dep-weight self-tests env-test facts-check loop-lint bench-test
+all: check test sim coverage size-metrics runtime-metrics am6 am7 am8 replay-test dep-weight self-tests env-test facts-check loop-lint bench-test