- New indicators: vwap (rolling/cumulative) and supertrend (line + direction), exposed on StrategyContext. - New strategies: supertrend (flip-based, optional shorts), vwap_reversion (mean reversion below a rolling VWAP) and ema_cross_short (short-side example, mirroring the long EMA cross). 10 strategies total. - Adds indicator and strategy tests; smoke-tested all three on live BTC/USDT 5m data.