Add weather.go with GetWeather() for extracting structured weather data
(location, temp, conditions, forecast) and stock.go with GetStockQuote()
and GetStockChart() for stock data extraction and chart screenshots.
Both include mock-based tests. CSS selectors may need tuning against
the live site since DuckDuckGo's React-rendered widgets use dynamic
class names.
Closes#25, #26
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
