Fix Backup info size display (#7540)

packages/core/src/backup.ts

@@ -10,6 +10,8 @@ export interface DocChunk {
   idx: number
   // _id => hash mapping
   docs: DocInfo[]
+
+  size?: number // Estimated size of the chunk data
   finished: boolean
 }
 

packages/core/src/server.ts

@@ -25,6 +25,8 @@ import type { WorkspaceIdWithUrl } from './utils'
 export interface DocInfo {
   id: string
   hash: string
+
+  size?: number
 }
 /**
  * @public