Three parameters were hardcoded with no way to override via config:
- count=20 in yf.Ticker.get_news() inside get_news_yfinance
- look_back_days=7 default in get_global_news_yfinance
- limit=10 default in get_global_news_yfinance
Add three new keys to DEFAULT_CONFIG:
- news_article_limit (default 20): max articles per ticker for get_news
- global_news_lookback_days (default 7): lookback window for get_global_news
- global_news_article_limit (default 10): max global articles for get_global_news
Both yfinance and alpha_vantage news implementations now read these values
from config, allowing users running weekly/monthly strategies to increase
coverage without modifying library source code.