[FEATURE] Compare/merge folders on a remote host over SSH

Description

Add support for comparing (and merging) a folder on a remote machine over SSH, without having to first mount the remote folder as a local drive with a third-party tool.

Right now the only way to diff a local folder against one on a remote Linux/Unix host is to mount the remote side first (e.g. with SSHFS-Win or rclone mount) and then open it as if it were a normal local path. It would be much more convenient to be able to connect directly from WinMerge (host, port, username, and password or key-based authentication) and pick a remote path the same way you'd pick a local one.

Examples or references (optional)

No response

Additional context

The current recommended workaround (mounting via SSHFS-Win or rclone, as suggested in #1901) works but requires installing and configuring a separate tool, and isn't always usable in restricted/managed environments where installing a filesystem driver isn't allowed.