fix(review): correct three wrong claims in this PR, and add the regression test

The diff was right; three things I wrote about it were not. An independent
reviewer falsified each one, and leaving a correct fix on an incorrect
rationale in git history is exactly what ALIGNMENT.md governance exists to
prevent. Corrections:

1. "No regression test is possible here" — WRONG, and the test is now here.
   Two compounding errors. `test-features.mjs:955` already has `ltBoot`, a
   real-server integration fixture (spawns server.mjs, fake claude binary,
   HTTP) that I had used myself in #191; I reasoned from "cannot import
   server.mjs" straight to "cannot test" without grepping for it. And the
   synchronous throw is reachable from ENV ALONE, needing no production hook:
   buildCliArgs does `args.push("--allowedTools", ...ALLOWED_TOOLS)`, and a
   spread of enough elements throws RangeError synchronously, inside the leak
   window. Measured, zero production changes:

     origin/main : 3 requests -> 500 x3 -> stats.activeRequests == 3
     this branch : 3 requests -> 500 x3 -> stats.activeRequests == 0

   The committed test DISCOVERS the element count rather than hard-coding it
   (the threshold is stack-size dependent, so a fixed number would silently
   stop triggering on another machine and pass vacuously), and asserts the
   requests actually 500 before trusting the counter. Mutation-proven: moving
   the increment back before the spawn fails it with "got 3".

2. My reason for rejecting #180's approach was WRONG. I claimed reconciling to
   activeProcesses.size is racy because a request that incremented but has not
   yet registered is invisible in the Set. There is no `await` anywhere in that
   window — it is fully synchronous, so on Node's single thread that state is
   unobservable and the race cannot occur. The real reason reconciliation is
   unsafe: the decrement is wired to 'exit' while activeProcesses.delete is
   wired to 'close', and exit precedes close (measured exit @2ms, close
   @2017ms with a grandchild holding stdout), so activeProcesses.size
   OVER-reports during that window — the opposite direction from what I wrote.
   Separately, a throw after activeProcesses.add leaves permanent Set residue
   that reconciliation would inherit. Corrected publicly on #180; the
   contributor was owed an accurate rejection.

3. The alignment citation named the wrong authority. ALIGNMENT.md:17 scopes
   Rules 1-5 to Class A only, and Rule 2 is a prohibition, not an
   authorization — citing it as justification is a category error. Every reader
   of stats.activeRequests is a grandfathered Class B.2 endpoint (/health,
   /status, /usage). Correct citation, per ALIGNMENT.md:142 and the in-repo
   precedent at server.mjs:3271-3276 (the F6 spawn.isolated fix):

     Authorized by ADR 0006 (grandfathered as of v3.16.4). The field SET is
     unchanged — no field added, removed or renamed — only the VALUE is made
     truthful. Behaviour-preserving; no new ADR required.

   The "cli.js: no hit, declared" part stands: cli.js has no equivalent
   operation, and spawn argv and protocol are byte-identical.

Also corrected the new comment at the increment: only 'exit' is wired inside
spawnClaudeProcess; 'close'/'error' are wired by each caller, and that is
REQUIRED because a failed spawn never emits 'exit'.

Note for a follow-up issue, not folded in (Iron Rule 11): stats.errors stays 0
across all of these 500s — synchronous throws from spawnClaudeProcess are never
counted. And CLAUDE.md hard-requirement #1 literally says "justify scope under
Rule 2", which is what I followed; CLAUDE.md predates ADR 0006's Class B
section and needs its own governance PR.

Tests: 450 passed, 0 failed.

Co-Authored-By: Hermes Agent <hermes-agent@users.noreply.github.com>
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017gbqUZ8HfBZpjjbzQ85oH8

test-features.mjs

@@ -1104,6 +1104,60 @@ test("integration: toggling OCP_LOCAL_TOOLS invalidates the standard response ca
   } finally { _ltRm(dir, { recursive: true, force: true }); }
 });
 
+// ── active-request counter is paired to the process lifecycle (#180 / #193) ──
+// The counter used to be incremented ~40 lines before the spawn, while its only decrement
+// (cleanup()) is wired to that proc's events — so any SYNCHRONOUS throw in between leaked +1
+// permanently. Driving that fault needs no production hook and no test double: buildCliArgs
+// does `args.push("--allowedTools", ...ALLOWED_TOOLS)`, and a spread of enough elements throws
+// RangeError synchronously, right inside the window.
+//
+// The element count is DISCOVERED, not hard-coded: the throw threshold depends on stack size,
+// so a fixed number would silently stop triggering on a machine with a bigger stack and the
+// test would pass vacuously. We find a count that throws in THIS process, then use it for the
+// child (same binary, same default stack). The test also asserts the requests actually 500 —
+// if the trigger ever stops firing, that assert fails loudly instead of going quietly green.
+function ltSpreadThrowCount() {
+  for (const n of [1 << 16, 1 << 17, 1 << 18, 1 << 19]) {
+    try { const probe = []; probe.push("--allowedTools", ...Array(n).fill("x")); }
+    catch { return n; }
+  }
+  return null;
+}
+async function ltPostStatus(port, body) {
+  try {
+    const r = await fetch(`http://127.0.0.1:${port}/v1/chat/completions`, {
+      method: "POST", headers: { "Content-Type": "application/json" }, body: JSON.stringify(body),
+    });
+    return r.status;
+  } catch { return 0; }
+}
+
+console.log("\nactive-request counter pairing (#180 / #193):");
+
+test("integration: a synchronous pre-spawn throw must not leak stats.activeRequests", async () => {
+  if (!LT_POSIX) return;
+  const n = ltSpreadThrowCount();
+  assert.ok(n, "could not find an element count whose spread throws — adjust ltSpreadThrowCount");
+  const dir = ltMkdir(); const fake = ltFake(dir);
+  const { child, buf } = ltBoot({
+    CLAUDE_BIN: fake, CLAUDE_PROXY_PORT: "39370",
+    CLAUDE_ALLOWED_TOOLS: Array(n).fill("x").join(","),
+  }, dir);
+  try {
+    assert.ok(await ltWait(() => buf.out.includes("listening on"), 20000), `did not start: ${buf.err.slice(0, 200)}`);
+    const req = { model: "haiku", messages: [{ role: "user", content: "leak-probe" }] };
+    const codes = [];
+    for (let i = 0; i < 3; i++) codes.push(await ltPostStatus(39370, req));
+    // Non-vacuous: if the spread stopped throwing these would be 200 and the counter would be
+    // 0 for the wrong reason. Assert the fault actually fired before trusting the counter.
+    assert.deepEqual(codes, [500, 500, 500], `expected the pre-spawn throw to surface as 500s, got ${codes}`);
+    const r = await fetch(`http://127.0.0.1:39370/status`);
+    const active = (await r.json()).requests.active;
+    assert.equal(active, 0,
+      `3 requests threw before their spawn; the counter must be back to 0, got ${active} (this is the #180 leak)`);
+  } finally { child.kill("SIGKILL"); _ltRm(dir, { recursive: true, force: true }); }
+});
+
 // ── Upgrade Tests ──
 import { runUpgrade, postFlightOk } from "./scripts/upgrade.mjs";