fix(persistent): serialize concurrent saveState calls to prevent data loss (#24)

Author: jettcc

.gitignore

@@ -5,3 +5,4 @@ dist/
 data/
 .agent-inbox/
 .worktrees/
+.DS_Store

packages/core/src/persist.ts

@@ -276,6 +276,8 @@ function mergeScopedObjectRecord<T extends object>(
   return merged;
 }
 
+let writeQueue: Promise<void> = Promise.resolve();
+
 async function readExistingPersistedState(): Promise<Partial<PersistedState>> {
   try {
     const raw = await readFile(config.stateFile, 'utf-8');
@@ -350,6 +352,26 @@ export async function saveState(
   threadContinuationSnapshots: Map<string, ThreadContinuationSnapshot>,
   savedCwdList: string[],
   options: StateScopeOptions = {},
+): Promise<void> {
+  const task = writeQueue.then(() => doSaveState(
+    sessions, models, effort, cwd, backend,
+    threadSessionBindings, threadContinuationSnapshots,
+    savedCwdList, options,
+  ));
+  writeQueue = task.catch(() => {});
+  return task;
+}
+
+async function doSaveState(
+  sessions: Map<string, string>,
+  models: Map<string, string>,
+  effort: Map<string, string>,
+  cwd: Map<string, string>,
+  backend: Map<string, string>,
+  threadSessionBindings: Map<string, ThreadSessionBinding>,
+  threadContinuationSnapshots: Map<string, ThreadContinuationSnapshot>,
+  savedCwdList: string[],
+  options: StateScopeOptions = {},
 ): Promise<void> {
   try {
     const existing = options.platform ? await readExistingPersistedState() : {};