v3.6.0

v3.6.0 — Backtesting Engine

• Historical OHLCV data layer with OANDA pagination and PostgreSQL cache
• FVG, Fibonacci (0.5/0.786) and liquidity sweep signal detectors
• Bar-by-bar backtest engine with Prophet risk rules (0.5–1% risk, 1:2/1:3 RR)
• Backtest results reporter — win rate, PnL, drawdown, top trades
• New agent tool: run_backtest — ask Prophet to backtest any pair