### Screen Lock

Hold **Back** and press **Enter** three times to lock or unlock the device. While locked:

- The display turns off and ignores incoming keypresses
- A brief button press shows the lock screen: current time, date, and up to two sensor values (reuses the Dashboard Config fields)
- A hint popup guides through the unlock sequence
- **Auto-lock** (configurable in Settings → System) locks automatically when the display turns off