feat: add controlled codex thread archive

tests/fixtures/codex-app-server-runtime.mjs

@@ -619,6 +619,42 @@ rl.on("line", (line) => {
     return;
   }
 
+  if (message.method === "thread/archive") {
+    send({
+      id: message.id,
+      result: {},
+    });
+    send({
+      method: "thread/archived",
+      params: {
+        threadId: message.params?.threadId,
+        archivedThreadSecret: "thread-archive-secret-should-not-leak",
+      },
+    });
+    return;
+  }
+
+  if (message.method === "thread/unarchive") {
+    send({
+      id: message.id,
+      result: {
+        thread: {
+          id: message.params?.threadId,
+          name: "private unarchived thread name should not leak",
+          archived: false,
+        },
+      },
+    });
+    send({
+      method: "thread/unarchived",
+      params: {
+        threadId: message.params?.threadId,
+        unarchivedThreadSecret: "thread-unarchive-secret-should-not-leak",
+      },
+    });
+    return;
+  }
+
   if (message.method === "thread/read") {
     send({
       id: message.id,