Fix kiosk operator UI on root test stations

Headless test jigs that run as root could no longer open the kiosk operator UI, leaving runs stuck on unit identification.

• Fixed the kiosk operator UI failing to start for foreground run --kiosk on root stations.
• Restored remote viewing of the kiosk over an SSH port-forward on headless machines.
• Kept the root station service hardened: its command channel still refuses to bind as root.