Run Linux restart commands inside a detached transient systemd user
service (systemd-run --user) so the restart survives the launching
terminal being killed and its logs can be inspected via journalctl.
Make the Updates panel actionable: every command has Copy and Run,
a single recommended all-in-one command is shown at the top, and the
rest are grouped as optional additional commands.
Running the suggested restart command from a PI WEB terminal kills the
command when sessiond restarts, so services listed after sessiond were
never restarted. Restart web/UI first in both the updates plugin's
suggested command and `pi-web restart` (systemd and launchd).