T07: Cargo workspace scaffold — cb-kernel/cb-events/cb-game-runtime/games-ground/cb-sim, HashMap deny-lint, scenario format + runner stub, Criterion skeleton, Makefile, CI

games/ground/benches/synthetic.rs

@@ -0,0 +1,49 @@
+//! Criterion skeleton for AM-6/AM-7 (GameKernel §4), wired to the
+//! CB-RES-0001 baseline shape (3-player commit/reveal synthetic workload).
+//! T08 replaces the placeholder body with the real aggregate loop; the
+//! bench IDs and workload sizes are fixed here so results stay comparable
+//! to benchmarks/baselines/ recordings.
+
+use cb_events::state_hash;
+use cb_game_runtime::CommitWindow;
+use cb_kernel::PlayerId;
+use criterion::{criterion_group, criterion_main, BatchSize, Criterion};
+
+/// Placeholder workload: open/submit/reveal one 3-player commit window and
+/// hash a small value. Exists so the bench harness, IDs, and baseline
+/// wiring compile and run before the aggregate exists.
+fn commit_reveal_round() -> usize {
+    let mut w: CommitWindow<u8> = CommitWindow::open([PlayerId(0), PlayerId(1), PlayerId(2)]);
+    for p in 0..3u8 {
+        w.submit(PlayerId(p), p).unwrap();
+    }
+    let revealed = w.reveal().unwrap();
+    state_hash(&revealed.len()).len()
+}
+
+fn bench_synthetic(c: &mut Criterion) {
+    let mut group = c.benchmark_group("synthetic-ground-3p");
+    // AM-6 headline workload sizes; AM-7 compares 5k vs 100k throughput.
+    for &rounds in &[5_000usize, 100_000] {
+        group.bench_function(format!("commit-reveal-{rounds}"), |b| {
+            b.iter_batched(
+                || rounds,
+                |n| {
+                    let mut acc = 0usize;
+                    for _ in 0..n / 1000 {
+                        // Scaffold runs 1/1000th scale until T08 wires the
+                        // real aggregate; the group/ID layout is what T07
+                        // delivers.
+                        acc += commit_reveal_round();
+                    }
+                    acc
+                },
+                BatchSize::SmallInput,
+            )
+        });
+    }
+    group.finish();
+}
+
+criterion_group!(benches, bench_synthetic);
+criterion_main!(benches);