Rain, storm, snow, and fog now have atmospheric ambient messages. Clear and cloudy conditions return empty list. Messages are evocative and lowercase, ready to be mixed with zone-specific ambience.
Implements procedural weather transitions with: - WeatherCondition enum (clear, cloudy, rain, storm, snow, fog) - WeatherState dataclass (condition + intensity 0-1) - get_weather_description() for atmospheric text varying by intensity - advance_weather() with probabilistic transitions based on season/climate - Climate profiles: temperate (balanced), arid (clear/rare rain), arctic (snow/fog/cloudy)
