feat(S-102): Test-drive and implement --timeout flag, config layering, and default in

tools/ai-cli-dispatch/tests/execute.test.ts

@@ -203,4 +203,58 @@ describe("executePrompt", () => {
         err instanceof ExecError && err.message.includes("Unknown client")
     );
   });
+
+  it("includes client and durationMs in result", async () => {
+    const scenarios = new Map<string, MockScenario>([
+      ["codex exec --yolo hello", { stdout: "ok", exitCode: 0 }],
+    ]);
+    const result = await executePrompt("codex", "hello", {
+      spawn: mockSpawn(scenarios),
+      existsSync: () => true,
+    });
+    assert.strictEqual(result.client, "codex");
+    assert.strictEqual(typeof result.durationMs, "number");
+    assert.ok(result.durationMs >= 0);
+  });
+
+  it("rejects with ExecError containing custom timeout value", async () => {
+    const scenarios = new Map<string, MockScenario>([
+      ["codex exec --yolo slow", { hang: true }],
+    ]);
+    await assert.rejects(
+      executePrompt("codex", "slow", {
+        spawn: mockSpawn(scenarios),
+        existsSync: () => true,
+        timeoutMs: 50,
+      }),
+      (err: unknown) =>
+        err instanceof ExecError &&
+        err.message === "Execution timed out after 50ms" &&
+        err.result.exitCode === -1 &&
+        err.result.client === "codex" &&
+        typeof err.result.durationMs === "number"
+    );
+  });
+
+  it("uses default timeout of 600000 when timeoutMs is not provided", async () => {
+    const delays: number[] = [];
+    const origSetTimeout = global.setTimeout;
+    (global as any).setTimeout = function(callback: any, delay: number) {
+      delays.push(delay);
+      return origSetTimeout(callback, delay);
+    };
+
+    const scenarios = new Map<string, MockScenario>([
+      ["codex exec --yolo hello", { stdout: "ok", exitCode: 0 }],
+    ]);
+    try {
+      await executePrompt("codex", "hello", {
+        spawn: mockSpawn(scenarios),
+        existsSync: () => true,
+      });
+      assert.strictEqual(delays[0], 600_000);
+    } finally {
+      global.setTimeout = origSetTimeout;
+    }
+  });
 });