Raspberry Pi Pico PWM LED Fade (Breathing Effect, GP14)

The LED no longer just blinks — it breathes! 🌬️ Using the Raspberry Pi Pico's **PWM** (Pulse Width Modulation), the LED brightness slowly rises and then slowly falls, like a sleeping MacBook's light. Learn the **machine.PWM class**, **duty_u16()** (16-bit brightness 0–65535), **PWM frequency** (`freq(1000)` — 1000 on/off cycles per second, no visible flicker), **range() step loops** (up and down) and **analog-like output** from a digital pin. PWM is a core embedded tool — RGB color mixing, motor