fix: stabilize memory sync progress

src/memory/manager.sync-errors-do-not-crash.test.ts

@@ -84,12 +84,12 @@ describe("memory manager sync failures", () => {
     // Call the internal scheduler directly; it uses fire-and-forget sync.
     (manager as unknown as { scheduleWatchSync: () => void }).scheduleWatchSync();
 
-    await vi.runAllTimersAsync();
+    await vi.runOnlyPendingTimersAsync();
     const syncPromise = syncSpy.mock.results[0]?.value as Promise<void> | undefined;
+    vi.useRealTimers();
     if (syncPromise) {
       await syncPromise.catch(() => undefined);
     }
-    await vi.runOnlyPendingTimersAsync();
 
     process.off("unhandledRejection", handler);
     expect(unhandled).toHaveLength(0);

src/memory/manager.ts

@@ -876,7 +876,9 @@ export class MemoryIndexManager {
     force?: boolean;
     progress?: (update: MemorySyncProgressUpdate) => void;
   }) {
-    const progress = params?.progress ? this.createSyncProgress(params.progress) : null;
+    const progress = params?.progress
+      ? this.createSyncProgress(params.progress)
+      : undefined;
     const vectorReady = await this.ensureVectorReady();
     const meta = this.readMeta();
     const needsFullReindex =