feat: add snjs package

packages/snjs/lib/Services/Sync/Signals.ts

@@ -0,0 +1,18 @@
+import { ServerSyncResponse } from '@Lib/Services/Sync/Account/Response'
+import { OfflineSyncResponse } from './Offline/Response'
+
+export enum SyncSignal {
+  Response = 1,
+  StatusChanged = 2,
+}
+
+export type SyncStats = {
+  completedUploadCount: number
+  totalUploadCount: number
+}
+
+export type ResponseSignalReceiver<T extends ServerSyncResponse | OfflineSyncResponse> = (
+  signal: SyncSignal,
+  response?: T,
+  stats?: SyncStats,
+) => Promise<void>