feat(bench): add safety number & epoch rotation benchmarks, CI workflow

Add safety_number benchmark to crypto_benchmarks.rs, epoch rotation
(propose_self_update + commit) benchmark to mls_operations.rs, expand
add_member group sizes to include 100, and add .github/workflows/bench.yml
that runs Criterion benchmarks and uploads HTML reports as artifacts.

crates/quicproquo-core/benches/crypto_benchmarks.rs

@@ -8,7 +8,7 @@
 
 use criterion::{black_box, criterion_group, criterion_main, BenchmarkId, Criterion};
 
-use quicproquo_core::{IdentityKeypair, padding};
+use quicproquo_core::{compute_safety_number, IdentityKeypair, padding};
 
 // ── Identity keypair benchmarks ──────────────────────────────────────────────
 
@@ -127,6 +127,17 @@ fn bench_padding(c: &mut Criterion) {
     group.finish();
 }
 
+// ── Safety number benchmarks ─────────────────────────────────────────────────
+
+fn bench_safety_number(c: &mut Criterion) {
+    let key_a = [0x1au8; 32];
+    let key_b = [0x2bu8; 32];
+
+    c.bench_function("safety_number", |b| {
+        b.iter(|| black_box(compute_safety_number(black_box(&key_a), black_box(&key_b))));
+    });
+}
+
 criterion_group!(
     benches,
     bench_identity_keygen,
@@ -134,5 +145,6 @@ criterion_group!(
     bench_identity_verify,
     bench_sealed_sender,
     bench_padding,
+    bench_safety_number,
 );
 criterion_main!(benches);

crates/quicproquo-core/benches/mls_operations.rs

@@ -62,8 +62,8 @@ fn bench_group_create(c: &mut Criterion) {
 
 fn bench_add_member(c: &mut Criterion) {
     let mut group = c.benchmark_group("mls_add_member");
-    // Smaller sizes to keep setup time reasonable
-    for size in [2, 10, 50] {
+    group.sample_size(10);
+    for size in [2, 10, 50, 100] {
         group.bench_with_input(BenchmarkId::from_parameter(size), &size, |b, &size| {
             b.iter_batched(
                 || {
@@ -83,6 +83,29 @@ fn bench_add_member(c: &mut Criterion) {
     group.finish();
 }
 
+fn bench_epoch_rotation(c: &mut Criterion) {
+    let mut group = c.benchmark_group("mls_epoch_rotation");
+    group.sample_size(10);
+    for size in [2, 10, 50] {
+        group.bench_with_input(BenchmarkId::from_parameter(size), &size, |b, &size| {
+            b.iter_batched(
+                || {
+                    let (mut creator, members) = setup_group(size);
+                    // Propose a self-update to simulate epoch rotation
+                    let proposal = creator.propose_self_update().unwrap();
+                    (creator, members, proposal)
+                },
+                |(mut creator, _members, _proposal)| {
+                    // Commit pending proposals (the self-update) to advance the epoch
+                    creator.commit_pending_proposals().unwrap();
+                },
+                BatchSize::SmallInput,
+            );
+        });
+    }
+    group.finish();
+}
+
 fn bench_send_message(c: &mut Criterion) {
     let mut group = c.benchmark_group("mls_send_message");
     for size in [2, 10, 50] {
@@ -127,6 +150,7 @@ criterion_group!(
     bench_keygen,
     bench_group_create,
     bench_add_member,
+    bench_epoch_rotation,
     bench_send_message,
     bench_receive_message,
 );