fix(feishu): route /btw through out-of-band lanes (#64324)

* fix(feishu): route /btw through out-of-band lanes

* fix(feishu): bound btw out-of-band lanes

* fix: route feishu btw out-of-band (#64324) (thanks @ngutman)

extensions/feishu/src/sequential-queue.ts

@@ -0,0 +1,15 @@
+export function createSequentialQueue() {
+  const queues = new Map<string, Promise<void>>();
+
+  return (key: string, task: () => Promise<void>): Promise<void> => {
+    const previous = queues.get(key) ?? Promise.resolve();
+    const next = previous.then(task, task);
+    queues.set(key, next);
+    void next.finally(() => {
+      if (queues.get(key) === next) {
+        queues.delete(key);
+      }
+    });
+    return next;
+  };
+}