feat: Multi-Pair Divergence Selection Strategy

- Extend regime detection to top 10 cryptocurrencies (45 pairs)
- Dynamic pair selection based on divergence score (|z_score| * probability)
- Universal ML model trained on all pairs
- Correlation-based filtering to avoid redundant positions
- Funding rate integration from OKX for all 10 assets
- ATR-based dynamic stop-loss and take-profit
- Walk-forward training with 70/30 split

Performance: +35.69% return (vs +28.66% baseline), 63.6% win rate

scripts/download_multi_pair_data.py

@@ -0,0 +1,47 @@
+#!/usr/bin/env python3
+"""
+Download historical data for Multi-Pair Divergence Strategy.
+
+Downloads 1h OHLCV data for top 10 cryptocurrencies from OKX.
+"""
+import sys
+sys.path.insert(0, '.')
+
+from engine.data_manager import DataManager
+from engine.market import MarketType
+from engine.logging_config import setup_logging, get_logger
+from strategies.multi_pair import MultiPairConfig
+
+logger = get_logger(__name__)
+
+
+def main():
+    """Download data for all configured assets."""
+    setup_logging()
+    
+    config = MultiPairConfig()
+    dm = DataManager()
+    
+    logger.info("Downloading data for %d assets...", len(config.assets))
+    
+    for symbol in config.assets:
+        logger.info("Downloading %s perpetual 1h data...", symbol)
+        try:
+            df = dm.download_data(
+                exchange_id=config.exchange_id,
+                symbol=symbol,
+                timeframe=config.timeframe,
+                market_type=MarketType.PERPETUAL
+            )
+            if df is not None:
+                logger.info("Downloaded %d candles for %s", len(df), symbol)
+            else:
+                logger.warning("No data downloaded for %s", symbol)
+        except Exception as e:
+            logger.error("Failed to download %s: %s", symbol, e)
+    
+    logger.info("Download complete!")
+
+
+if __name__ == "__main__":
+    main()