docs: add API references, mapping corrections, and verification script
- Add yfinance.org and defeatbeta-api.org reference docs
- Fix defeatbeta_mapping.org: deprecated yfinance property names
(quarterly_financials→quarterly_income_stmt, financials→income_stmt),
longName vs longBusinessSummary conceptual mismatch, cashflow note typo
- Add Mapping Limitations section with live verification results (AAPL):
DuckDB 1.4.3 incompatibility, format differences, coverage gaps
- Add docs/test_mapping.py as runnable mapping verification script
- Add offline.py, persistent_cache.py, download_data.py, warmup_cache.py
for offline/cached defeatbeta usage
- Add aapl_yfinance.py exploration script and quant.py scaffold
- Add .envrc (uv layout) and update pyproject.toml + uv.lock
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
tomatocream
b5bf689e72