- rebuilt BTC/ETH from Deribit mainnet (certified 1.7-1.9bps vs Coinbase)
- archived contaminated alt data to Old/data/raw
- add src/backtest/harness.py: leakage-free, fee-aware signal engine
(entry at close[i], intrabar TP/SL, CAGR/Sharpe/DD/per-year/OOS)