The nixpkgs attribute for userspace GPIO tools is 'libgpiod',
not 'gpiod'. This provides the gpioset binary used by the
GPIO 23 internal USB hub service.
- Add disko flake input + partition config (/boot/firmware, /, /home)
- Add cm5-backlight-fix service as display fallback
- Add enable-gpio23-usb-hub service for internal USB hub
- Add mt7921u kernel module for MediaTek AC1200 WiFi
- Add gpiod package for GPIO userspace control