feat(infra): new doc sync engine (#6205)

https://github.com/toeverything/AFFiNE/blob/eyhn/feat/new-sync/packages/common/infra/src/workspace/engine/doc/README.md

packages/frontend/core/src/modules/infra-web/storage/index.ts

@@ -4,6 +4,17 @@ import { Observable } from 'rxjs';
 export class LocalStorageMemento implements Memento {
   constructor(private readonly prefix: string) {}
 
+  keys(): string[] {
+    const keys: string[] = [];
+    for (let i = 0; i < localStorage.length; i++) {
+      const key = localStorage.key(i);
+      if (key && key.startsWith(this.prefix)) {
+        keys.push(key.slice(this.prefix.length));
+      }
+    }
+    return keys;
+  }
+
   get<T>(key: string): T | null {
     const json = localStorage.getItem(this.prefix + key);
     return json ? JSON.parse(json) : null;
@@ -29,6 +40,16 @@ export class LocalStorageMemento implements Memento {
     channel.postMessage(value);
     channel.close();
   }
+
+  del(key: string): void {
+    localStorage.removeItem(this.prefix + key);
+  }
+
+  clear(): void {
+    for (const key of this.keys()) {
+      this.del(key);
+    }
+  }
 }
 
 export class LocalStorageGlobalCache