fix: serialize local-agent heartbeats

local-agent/serialized-runner.mjs

@@ -0,0 +1,16 @@
+export function createSerializedRunner(task) {
+  let activePromise = null;
+
+  return function runSerialized(...args) {
+    if (activePromise) {
+      return activePromise;
+    }
+
+    activePromise = Promise.resolve(task(...args))
+      .finally(() => {
+        activePromise = null;
+      });
+
+    return activePromise;
+  };
+}