feat: Add weather awareness system (Issue #442)
Implements sensor fusion for environmental monitoring and adaptive outdoor behavior:
- BME280 environmental sensor (temperature, humidity, pressure)
- Phone weather API fallback (wind speed, conditions)
- Camera-based rain detection (image gradient analysis)
- WeatherState.msg with condition bitmask and recommendations
- Behavior triggers: rain→seek shelter, wind→reduce speed, extreme temp→warning
- Facial expressions: squint (rain), shiver (cold), relax (comfortable)
- Real-time publishing: /saltybot/weather (WeatherState), /saltybot/weather_alert (String)
- Adaptive thresholds: temp_min_safe, temp_max_safe, wind_threshold
Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
sl-perception
dc6eea4016