review: adversarial pass — fix ROI leak for overturned rows + load-gen guards

Two defects found and fixed in a hostile review of the whole package:

1. The ROI report generator trusted the ledger verdict field and would
   mint a clean $16,886/year report for phase2-comrak-010 — the
   memory-leaking patch the audit overturned (immutably 'accepted' in the
   append-only ledger, sanitizers_clean:false). report_row now exposes
   sanitizers_clean and the report treats accepted-but-not-sanitizer-clean
   as NOT shippable, printing a warning before any dollar figure. Legit
   wins (sanitizers_clean:true) still render clean.
2. bench-runner service --rate 0 / --count 0 could panic via
   from_secs_f64(1/0); run_session now guards finite/positive rate and
   non-zero count/workers.

Attacks correctly refused (verified, no change): ledger UPDATE/DELETE,
propose_patch ../ + .git escapes, read_target_source traversal. All 10
accepted rows satisfy the green-gates + CI>=1.02 invariant. Findings
recorded in results/adversarial-review.md.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EcKPWQ3MQD4NdEHwar96u2

crates/bench-runner/src/service.rs

@@ -189,6 +189,15 @@ fn one_request(port: u16) -> std::io::Result<()> {
 
 /// One open-loop load session against a freshly spawned server.
 pub fn run_session(cfg: &ServiceCfg, port: u16) -> Result<SessionResult> {
+    ensure!(
+        cfg.rate.is_finite() && cfg.rate > 0.0,
+        "arrival rate must be finite and positive (got {})",
+        cfg.rate
+    );
+    ensure!(
+        cfg.count > 0 && cfg.workers > 0,
+        "count and workers must be > 0"
+    );
     let mut child = spawn_server(cfg, port)?;
     // Warm up closed-loop (untimed) so the first timed request doesn't eat
     // page faults / cold caches.

crates/ledger/src/lib.rs

@@ -217,12 +217,30 @@ impl Ledger {
                     .and_then(|b| b.get("env_fingerprint"))
                     .and_then(|f| f.get("workload"))
                     .cloned();
+                // Pull the sanitizer gate out so the report can refuse to
+                // mint a clean ROI for an `accepted` row that predates the
+                // machine-enforced sanitizer gate and was overturned by
+                // audit (phase2-comrak-010). The gates JSON is stored
+                // separately; read it here.
+                let sanitizers_clean = self
+                    .conn
+                    .query_row(
+                        "SELECT gates FROM attempts WHERE run_id = ?1",
+                        [run_id],
+                        |r| r.get::<_, Option<String>>(0),
+                    )
+                    .ok()
+                    .flatten()
+                    .and_then(|g| serde_json::from_str::<serde_json::Value>(&g).ok())
+                    .and_then(|g| g.get("sanitizers_clean").and_then(|v| v.as_bool()))
+                    .unwrap_or(false);
                 Ok(Some(serde_json::json!({
                     "run_id": run_id,
                     "target": target,
                     "playbook_class": class,
                     "hypothesis": hypothesis,
                     "verdict": verdict,
+                    "sanitizers_clean": sanitizers_clean,
                     "timestamp": ts,
                     "speedup_median": bench.as_ref().and_then(|b| b.get("speedup_median").cloned()),
                     "speedup_ci": bench.as_ref().and_then(|b| b.get("speedup_ci").cloned()),

crates/report/src/main.rs

@@ -69,14 +69,27 @@ fn main() -> Result<()> {
         "**Target:** {target} · **Playbook class:** {class} · **Verdict:** `{verdict}`\n\n\
          **Workload:** {workload}\n\n",
     ));
-    // A report for anything the pipeline did not accept must say so before
-    // any dollar figure — the ROI below is a measured effect, not a
-    // shippable saving.
-    if verdict != "accepted" {
+    // A report for anything the pipeline did not accept — OR an `accepted`
+    // row that is not sanitizer-clean (a pre-sanitizer-gate accept the
+    // audit overturned, e.g. phase2-comrak-010) — must say so before any
+    // dollar figure. The ROI below is a measured effect, not a shippable
+    // saving. This closes the hole where the immutable ledger's historical
+    // accept could mint a clean ROI for a patch that was never shipped.
+    let sanitizers_clean = row["sanitizers_clean"].as_bool().unwrap_or(false);
+    let shippable = verdict == "accepted" && sanitizers_clean;
+    if !shippable {
+        let reason = if verdict != "accepted" {
+            format!("its verdict is `{verdict}`, not `accepted`")
+        } else {
+            "it is `accepted` but NOT sanitizer-clean — this is a pre-sanitizer-gate accept that \
+             the audit overturned (the immutable ledger preserves the original verdict; \
+             `sanitizers_clean:false` is the disqualifying signal)"
+                .to_string()
+        };
         md.push_str(&format!(
-            "> ⚠️ **Not shipped.** This attempt's verdict is `{verdict}`, not `accepted`. Any ROI\n\
-             > below is the *measured* effect — it did not clear the significance/tier bar and is\n\
-             > **not** a committed saving. Shown for completeness; the ledger records it as-is.\n\n",
+            "> ⚠️ **Not shipped.** This attempt is not a committed saving because {reason}. Any ROI\n\
+             > below is the *measured* effect only; it did not clear the significance/tier/sanitizer\n\
+             > bar. Shown for completeness; the ledger records it as-is.\n\n",
         ));
     }