feat: fork codex threads

tests/local-agent-codex-app-server-runner.test.mjs

@@ -1714,6 +1714,36 @@ test("codex app-server runner syncs thread git metadata without starting a norma
   assert.doesNotMatch(JSON.stringify(result), /thread-metadata-secret-should-not-leak/);
 });
 
+test("codex app-server runner forks a thread without starting a normal turn", async () => {
+  const runnerConfig = getCodexAppServerRunnerConfig(process.env, {
+    codexAppServerEnabled: true,
+    codexAppServerCommand: process.execPath,
+    codexAppServerArgs: ["tests/fixtures/codex-app-server-runtime.mjs"],
+    codexAppServerWorkdir: repoRoot,
+    codexAppServerTimeoutMs: 5000,
+  });
+
+  const result = await executeCodexAppServerTask(runnerConfig, {
+    taskId: "task-thread-fork",
+    taskType: "conversation_reply",
+    intentCategory: "thread_fork",
+    targetCodexThreadRef: "019d-app-server-thread",
+    targetCodexFolderRef: repoRoot,
+    threadForkEphemeral: false,
+    executionPrompt: "分叉当前 Codex 线程。",
+  });
+
+  assert.equal(result.status, "completed");
+  assert.equal(result.threadId, "019d-app-server-thread");
+  assert.equal(result.turnControl, "fork");
+  assert.equal(result.threadFork?.sourceThreadId, "019d-app-server-thread");
+  assert.equal(result.threadFork?.forkedThreadId, "019d-app-server-thread-fork");
+  assert.equal(result.threadFork?.forkedThreadName, "Forked working thread");
+  assert.equal(result.threadFork?.ephemeral, false);
+  assert.equal(result.turnId, undefined);
+  assert.doesNotMatch(JSON.stringify(result), /thread-fork-secret-should-not-leak/);
+});
+
 test("codex app-server runner stays disabled unless feature flag is explicit", () => {
   const runnerConfig = getCodexAppServerRunnerConfig(process.env, {
     codexAppServerCommand: process.execPath,