fix(pool): a Codex ChatGPT pool pane runs on the login placed for it

Codex >= 0.164 hands a plain TUI (no -c override) to the CODEX_HOME's
shared app-server daemon, which outlives every TUI and keeps the login it
started with. A ChatGPT pool account written into a member's auth.json
therefore reached no pane while their daemon still ran on the previous
login (reproduced on 0.164.0: the daemon kept sending the old key, a
--no-daemon TUI sent the new one). Such a pane now runs `codex
--no-daemon`, only when that binary's --help lists the flag (probed once
per path/size/mtime), so an older Codex still starts.

server/__tests__/codex-pool.test.js

@@ -243,6 +243,29 @@ describe("codex pool: spawn", () => {
     assert.equal(row.account, "c");
   });
 
+  it("runs a ChatGPT pane without the shared daemon, only when its Codex has the flag", () => {
+    // The home's app-server daemon keeps the login it started with: a placed
+    // login reaches only a pane that runs its own app server.
+    const fakeCodex = (name, help) => {
+      const file = path.join(TMP, name);
+      fs.writeFileSync(file, `#!/bin/sh\necho '${help}'\n`, { mode: 0o755 });
+      return file;
+    };
+    const prev = process.env.AGENTHUB_CODEX_BIN;
+    try {
+      pool.addAccount("c", { auth: AUTH("acct-c") });
+      process.env.AGENTHUB_CODEX_BIN = fakeCodex("codex-new", "      --no-daemon  Run without");
+      assert.deepEqual(pool.forSpawn(MIA).argv, ["--no-daemon"]);
+      process.env.AGENTHUB_CODEX_BIN = fakeCodex("codex-old", "      --oss  Use a local model");
+      assert.deepEqual(pool.forSpawn(MIA).argv, [], "an older Codex would refuse the flag");
+      process.env.AGENTHUB_CODEX_BIN = path.join(TMP, "no-such-codex");
+      assert.deepEqual(pool.forSpawn(MIA).argv, []);
+    } finally {
+      if (prev === undefined) delete process.env.AGENTHUB_CODEX_BIN;
+      else process.env.AGENTHUB_CODEX_BIN = prev;
+    }
+  });
+
   it("never replaces a member's own login, and stays on the account their live pane uses", () => {
     pool.addAccount("c", { auth: AUTH("acct-c") });
     pool.addAccount("d", { auth: AUTH("acct-d") });
@@ -272,7 +295,10 @@ describe("codex pool: spawn", () => {
     fs.writeFileSync(MIA_AUTH, JSON.stringify(own));
     assert.equal(pool.pickAccount(MIA), null);
     pty.spawnRun({ laneId: 50, cwd: path.join(MIA.home, "p"), tool: "codex" });
-    assert.equal(JSON.parse(fs.readFileSync(MIA_AUTH, "utf8")).tokens.refresh_token, "rt-mias-seat");
+    assert.equal(
+      JSON.parse(fs.readFileSync(MIA_AUTH, "utf8")).tokens.refresh_token,
+      "rt-mias-seat"
+    );
   });
 
   it("copies the newest auth.json back into the pool", () => {