Run remote hosts on Windows over direct SSH

[thesiti92]

Turns remote hosts back on for Windows laptops (reverting #1110's early return) with direct sessions from #1113.

• The inbox %SystemRoot%\System32\OpenSSH\ssh.exe is used when present, ahead of an MSYS ssh (Git for Windows) on PATH.
• ssh runs with windowsHide and not detached; a detached ssh gets a console window on Windows.
• Windows needs a key ssh-agent can use and a host already in known_hosts. A refused key says to use ssh-add; an unknown host key already says to run ssh <alias> in a terminal.
• Include globs in ssh_config take forward slashes on Windows.
• docs/remote-hosts.md: the Windows setup.

Checked in a Windows 11 VM (24H2, ARM64, inbox OpenSSH 9.5p1) against a Linux container with the real modules and the Desktop's spawn options: picks the inbox ssh.exe; exec and the probe run with no prompt and no window; uploadFile is byte-exact into a path with a space; the -D master, a forward to the host's sshd and a held -R round trip work; an unknown host key and an unauthorized key fail fast with ssh's own messages; an Include with a Windows path lists its aliases; no ssh.exe is left after. A dev build of this branch also ran in that VM (ARM64 Electron), against a Linux host with Whiteboard on its PATH, using an ssh-agent key: online in 10 s, /health through the SOCKS forward, a killed master recovered in under 2 s, and a normal quit left no ssh.exe. Dev-only gaps on Windows ARM64, unrelated to this change, kept it from the UI and the dev install: run.sh looks for review rather than Whiteboard.exe and hands MSYS paths to node, the curated extensions and diffr have no win32-arm64 target, and the dev pack (pnpm pack) fails there.

Stacked on #1113.