//! CCT (colour-temperature) light — two PWM channels, cool-white and warm-white.
//!
//! Two supported wirings:
//!
//! Default (active-high, for real loads): each GPIO drives a low-side
//! N-MOSFET/transistor that carries the channel current.
//! lamp+ → supply rail (e.g. 12/24 V)
//! GPIO_COOL → cool MOSFET gate, drain → W−, source → GND
//! GPIO_WARM → warm MOSFET gate, drain → Y−, source → GND
//!
//! Direct GPIO sink (tiny 3V lamps only, within the GPIO current limit) — the
//! negative wires are soldered straight to the GPIOs, which sink the current;
//! add `.inverted()` so the driver reverses the electrical duty:
//! lamp+ → 3V3
//! W− → GPIO_COOL
//! Y− → GPIO_WARM
//!
//! Adjust the GPIO numbers to match your hardware.
//! `.mac()` is optional; omit it to let the ESP32 use its built-in MAC.
//! `.reset_pin()` enables factory reset: hold the pin low at boot to unpair.
//!
//! Reference code, not standalone firmware — see `examples/README.md`.