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
- New PixelStompMux class with shift register read/write
- Read 10 buttons via DI (active LOW)
- Drive 10 LEDs via DAT (shift out + latch)
- LED startup animation uses MUX
- Switch polling reads from MUX shift register
- MUX instance shared between switch and LED drivers
- Replace ESP-IDF structure with PlatformIO (platformio.ini)
- Move source files to src/ and include/
- Move libraries to lib/ directory
- Replace FreeRTOS with Arduino task/vTaskDelay
- Use Arduino MIDI library instead of raw TinyUSB
- Dual-core: MIDI on core 0, controller on core 1
ash