btrbk archive to ssh://

Hi, with btrbk archive I can transfer snapshots to a new local destination, but it fails to transfer to a new ssh:// destination like this:

`btrbk --progress archive /mnt/local/data/snapshots/mobalindesk/root/root.20250815T050000+0200/ ssh://molinsrv/mnt/local/data/snapshots/mobalindesk/root `

Reproduce the failure with the reported `btrbk --progress archive` command, comparing the working local destination with the `ssh://` destination. Trace the archive command's remote-destination handling; the issue is done when archiving to the reported SSH destination succeeds like the local transfer.

Written by the indexing model from the issue text.