Update yfinance, python, improve rate limiting

• Require Python 3.10+ (drop 3.9 support)
• Require yfinance >=0.2.58 for curl_cffi (fixes Yahoo rate limiting)
• Update dependencies: pendulum >=3.0, pycoingecko >=3.0, seaborn >=0.12
• Fix infinite retry loop when rate limited (add max_tries check)
• Catch yfinance YFRateLimitError and convert to RateLimitHitError
• Replace deprecated raise_errors param with yf.config setting
• Convert Yahoo caching test to mocked unit test (faster, more reliable)
• Fix pyproject.toml section name typo
• Update documentation