When the host shuts down, sshd is killed before sending exit-status,
causing Go ssh library to return "wait: remote command exited without
exit status" — treated as failure even though the shutdown worked.
Changes:
- shutdown.go: wrap shutdown-like commands with nohup so the SSH
session exits cleanly before sshd is killed by shutdown
- IsShutdownCommand() helper detects shutdown/poweroff/halt/reboot commands
- handlers_machines.go: classify expected shutdown-side-effect errors
(no exit status, connection refused/reset) as success so the UI
shows a green toast instead of a false error
darroyo
f476b7bd8b