feat: implement region-based QR code scanning for inbox documents

paperless-backend/src/database/entities/inbox-document.entity.ts

@@ -32,6 +32,9 @@ export class InboxDocument {
   @Column({ type: 'int', default: 0 })
   PageCount!: number;
 
+  @Column({ type: 'boolean', default: true })
+  IsScanned!: boolean;
+
   @Column({ type: 'json' })
   QrCodes!: StoredQrCode[];