Run all 9 strategies (RSI, Bollinger, MACD, EMA Cross, Supertrend, Donchian, RSI Pullback, Keltner Breakout, Triple EMA) and return a ranked leaderboard.

    Args:
        symbol: Yahoo Finance symbol (AAPL, BTC-USD, SPY…)
        period: '1mo', '3mo', '6mo', '1y', '2y'
                (period >= '1y' recommended so rsi_pullback and triple_ema can
                 complete SMA200 warmup; otherwise they contribute zero trades)
        initial_capital: Starting capital in USD (default $10,000)
        interval: '1d' (daily) or '1h' (hourly)