CB-WP-0006 T07: implement K18, amend K14

Two rules, two different answers, which is the point of a task phrased
"implement, or amend and say why".

K18 is implemented. "Criterion benches driving the same scenario format at
scale" was false — the bench hardcoded its commands and never touched
ScenarioFile, while MetricsAndScenarios §3 pointed at a benchmarks/
directory containing only baselines/. benchmarks/synthetic-3p.yaml now
holds the workload and both the bench and bench_shape read it: the
workload is data, not code.

A second defect surfaced while fixing the first. After the bench switched
to the file, bench_shape still hardcoded the same sequence, so the
workload existed twice — deleting end_round from the YAML broke bench-test
while bench_shape kept passing. Duplicated-fact drift in executable form.
Both now read the same include_str! and deleting a command breaks both.

Explicitly not claimed: this does not unblock AM-3. AM-3's baseline is a
declarative game object — moves, turn order, rules. synthetic-3p.yaml is a
command list; the rules live in games/ground. Marking it as AM-3's subject
would compare a script to a game definition, which is the category error
AM-3 is blocked on. The file says so in its own header, where the next
person will be tempted.

K14 is amended. CommitWindow had zero non-test users and GROUND enforces
the same contract inline. Wiring GROUND through it was rejected: it would
change the serialized shape of `selections`, which four scenario files
assert by dot-path and every state hash depends on, for the sole benefit
of making a sentence literally true.

The deciding argument is INTENT's, not convenience: abstractions are
extracted from working games rather than invented in isolation, and no
concept becomes canonical until it survives a second concrete use.
CommitWindow was invented before any game needed it and has survived none.
Imposing it on GROUND would manufacture the first use rather than discover
it. So K14 states what is actually guaranteed, CommitWindow is marked
provisional in the source, and it carries a delete-by date of 2026-12-31.

Kernel spec->code link 16/18 -> 18/18, stated with the caveat the gate
prints every run: that is about names, not assertions.

Two self-tests broke and both broke correctly. rule-coverage's gate test
hardcoded "unlinked rules exist today" and failed when the last one was
linked; it now computes that and asserts the gate fails iff rules are
unlinked. facts' text check rejected k_unlinked once it became
legitimately empty; empty now renders as "(none)" and the check
distinguishes absent from empty.

M-D1-MUT: 8 of 14, unchanged — K14 and K18 are kernel rules, not
acceptance rows.

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

history/260801-cb-wp-0006-log.md

@@ -334,3 +334,80 @@ immediately caught the spec's copy of that number going stale — the DFD
 gate earning its place on a number that moved the same hour.
 
 **M-D1-MUT: 8 of 14** (unchanged; AM-7 remains partial).
+
+## CB-WP-0006-T07
+
+**Two rules, two different answers — which is the point of a task phrased
+"implement, or amend and say why".**
+
+### K18: implemented
+
+"Criterion benches driving the same scenario format at scale" was false —
+the bench hardcoded its command sequence in Rust and never touched
+`ScenarioFile`, while MetricsAndScenarios §3 pointed at a `benchmarks/`
+directory containing only `baselines/`.
+
+`benchmarks/synthetic-3p.yaml` now holds the workload, and both the bench
+and `bench_shape` read it. **The workload is data, not code.**
+
+**A second defect surfaced while fixing the first.** After the bench
+switched to the file, `bench_shape` still hardcoded the same sequence — so
+the workload existed **twice**, and deleting `end_round` from the YAML
+broke `bench-test` while `bench_shape` kept passing. That is
+duplicated-fact drift in executable form. Both now read the same
+`include_str!`, and deleting a command breaks both:
+
+```text
+assertion `left == right` failed: commands per synthetic round
+```
+
+**Explicitly not claimed:** this does *not* unblock AM-3. AM-3's baseline
+is a declarative **game object** (~36 LOC, boardgame.io) — moves, turn
+order, rules. `synthetic-3p.yaml` is a command list; the rules live in
+`games/ground` (1,575 lines). Marking it as AM-3's subject would compare a
+script to a game definition, which is the category error AM-3 is blocked
+on. The file says so in its own header, where the next person will be
+tempted.
+
+### K14: amended, and the reasoning is recorded because it could have gone
+the other way
+
+`CommitWindow` had **zero non-test users**; GROUND enforces the same
+contract inline. Wiring GROUND through it was rejected: it would change
+the serialized shape of `selections`, which four scenario files assert by
+dot-path and every state hash depends on — a large, risky refactor whose
+only benefit is making a sentence literally true.
+
+The deciding argument is INTENT's, not convenience: *"abstractions are
+extracted from working games... rather than invented in isolation"*, and
+*"No concept becomes canonical merely because it looks general. It becomes
+canonical after surviving a second concrete use."* `CommitWindow` was
+invented before any game needed it and has survived **zero** uses.
+Imposing it on GROUND would **manufacture** the first use rather than
+discover it.
+
+So K14 now states what is actually guaranteed, `CommitWindow` is marked
+**provisional in the source**, and it carries a **delete-by date of
+2026-12-31** if no second game uses it. A primitive with one hypothetical
+user and a test that exercises only itself is the AM-11 shape, and this
+project has now paid for that shape twice.
+
+### Consequences
+
+**Kernel spec→code link: 16/18 → 18/18 (100%).** Stated with the caveat
+the gate prints on every run: that is a statement about **names**, not
+assertions.
+
+Two self-tests broke and both broke *correctly*:
+
+* `rule-coverage`'s gate test hardcoded "unlinked rules exist today" and
+  failed the moment the last one was linked. It now computes whether
+  anything is unlinked and asserts the gate fails **iff** so — the
+  assertion was right, its premise was transient.
+* `facts`' "every fact records a value and its rendered text" rejected
+  `k_unlinked` once it became legitimately empty. Empty now renders as
+  `(none)`, and the check distinguishes *absent* from *empty*.
+
+**M-D1-MUT: 8 of 14, unchanged.** K14 and K18 are kernel rules, not
+acceptance rows, so neither moves that number — worth stating, because the
+temptation is to imply progress on a metric this task never touched.