Build a backup and hand it to consume as a stream, for destinations
written over the network (S3, SFTP) or straight to a browser, where no
local copy is wanted. The archive is produced as the consumer reads it,
so only a few buffers of it exist at a time.
Create backup
Functionextract: (fnm: string, dir: string, password?: string) => Promise<void>Extract a zip file into a directory
Restore from backup
The name a backup taken now gets, e.g. sc-backup-Saltcorn-2026-08-14-09-15.zip