Add news API integration and related configurations

- Update .env.example to include NEWS_API_KEY configuration
- Add newsapi-python dependency in pyproject.toml
- Implement NewsAPI class for fetching news articles
- Create Article model for structured news data
- Add tests for NewsAPI functionality in test_news_api.py
- Update pytest configuration to include news marker

src/app/news/__init__.py

@@ -0,0 +1,3 @@
+from .news_api import NewsAPI
+
+__all__ = ["NewsAPI"]