feat(nbstore): init (#7639)

TODO

- [x] basic
- [x] storages
- [x] producer/consumer
- [x] operation pattern
- [x] events
- [x] worker
- [x] readme
- [x] peer dependencies

packages/common/nbstore/src/storage/sync.ts

@@ -0,0 +1,16 @@
+import type { DocClock, DocClocks } from './doc';
+import { Storage, type StorageOptions } from './storage';
+
+export interface SyncStorageOptions extends StorageOptions {}
+
+export abstract class SyncStorage<
+  Opts extends SyncStorageOptions = SyncStorageOptions,
+> extends Storage<Opts> {
+  override readonly storageType = 'sync';
+
+  abstract getPeerClocks(peer: string): Promise<DocClocks>;
+  abstract setPeerClock(peer: string, clock: DocClock): Promise<void>;
+  abstract getPeerPushedClocks(peer: string): Promise<DocClocks>;
+  abstract setPeerPushedClock(peer: string, clock: DocClock): Promise<void>;
+  abstract clearClocks(): Promise<void>;
+}