07e5cd8994
PixelStomp MUX uses: - WS2812C LEDs: one data line via DAT (GPIO 9), NeoPixel protocol - 74HC165 shift register: LD/CLK/DI for reading 8 button states Changes: - Use Adafruit NeoPixel library for LED control - Proper 74HC165 parallel-load shift-in for buttons - 8 switches + 8 LEDs (was incorrectly 10) - Diagnostic commands: dump, ledtest, red, green, blue, read