Implements STM32F722 driver for brushless cooling fan on PA9 using TIM1_CH2 PWM.
Features:
- Temperature-based speed curve: off <40°C, 30% at 50°C, 100% at 70°C
- Smooth speed ramp transitions with configurable rate (default 0.05%/ms)
- Linear interpolation between curve points
- PWM duty cycle control (0-100%)
- State transitions and edge case handling
All 51 unit tests passing:
- Temperature curve verification (6 test zones)
- Speed boundaries and transitions
- Ramp timing and rate control
- PWM duty cycle calculation
- Temperature extremes and boundary conditions
Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
