Get weather forecast for a city

Retrieve weather forecast information for a specified location using WeatherAPI.com. **Features:** - Multi-day weather forecasts (1-7 days) - Support for city names or coordinates (lat/lon) - Detailed daily weather information including min/max temperatures - Precipitation chance and wind information - Support for multiple temperature units - Authentication required for all requests **Location Input:** - **City-based**: Provide `city` parameter (e.g., "London", "New York") - **Coordinate-based**: Provide `lat` and `lon` parameters (e.g., 51.5074, -0.1278) - Either city OR coordinates must be provided **Forecast Information:** - Daily high/low temperatures - Weather conditions and descriptions - Humidity and wind speed - Precipitation probability - Weather icons for UI display **Authentication:** - Requires valid Bearer token - Test tokens available for development: `test-jwt-token`, `agent-jwt-token` - Production tokens verified with external auth service **Rate Limits:** - Subject to WeatherAPI.com rate limits - 10-second timeout for external API calls **Examples:** - 3-day forecast for London: `/api/context/weather/forecast?city=London` - 7-day forecast for New York: `/api/context/weather/forecast?city=New%20York&days=7` - Imperial units for Tokyo: `/api/context/weather/forecast?city=Tokyo&units=imperial&days=5` - Coordinates: `/api/context/weather/forecast?lat=51.5074&lon=-0.1278&days=3`