Add three new gems for I2C communication:
- hw-i2c: common Ruby API, C bindings, and HAL header
- hw-esp32-i2c: ESP32 HAL using ESP-IDF I2C master driver
- hw-rp2040-i2c: RP2040 HAL using Pico SDK
The HAL API provides init, read, write, and atomic write_read
(repeated START) operations. Platform gems depend on hw-i2c
and are only compiled when explicitly included in build config.
Co-authored-by: Claude <noreply@anthropic.com>
Yukihiro "Matz" Matsumoto