Implements STM32F722 driver for WS2812 NeoPixel 8-LED ring with finite state machine.
Features:
- 8 operational states with animations:
* BOOT: Blue pulse (0.5 Hz)
* IDLE: Green breathe (0.5 Hz)
* ARMED: Solid green
* NAV: Cyan spin (1 Hz)
* ERROR: Red flash (2 Hz)
* LOW_BATT: Orange blink (1 Hz)
* CHARGING: Green fill (1 Hz)
* ESTOP: Red solid
- Non-blocking tick-based animation system
- State transitions via API
- PWM control on PB4 (TIM3_CH1) at 800 kHz
- Color interpolation for smooth effects
All 25 unit tests passing covering state transitions, animations, timing, and edge cases.
Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
