fix: resolve 6 warning issues from code review

5. Add daily PnL reset loop — UTC midnight auto-reset via
   _daily_reset_loop in main.py, prevents stale daily_pnl accumulation
6. Fix set_base_balance race condition — call once in main.py before
   spawning bots, instead of each bot calling independently
7. Remove realized_pnl != 0 from close detection — prevents entry
   orders with small rp values being misclassified as closes
8. Rename xrp_btc_rs/xrp_eth_rs → primary_btc_rs/primary_eth_rs —
   generic column names for multi-symbol support (dataset_builder,
   ml_features, and tests updated consistently)
9. Replace asyncio.get_event_loop() → get_running_loop() — fixes
   DeprecationWarning on Python 3.10+
10. Parallelize candle preload — asyncio.gather for all symbols
    instead of sequential REST calls, ~3x faster startup

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

main.py

@@ -1,4 +1,5 @@
 import asyncio
+from datetime import datetime, timedelta, timezone
 from dotenv import load_dotenv
 from loguru import logger
 from src.config import Config
@@ -9,18 +10,39 @@ from src.logger_setup import setup_logger
 load_dotenv()
 
 
+async def _daily_reset_loop(risk: RiskManager):
+    """매일 UTC 자정에 daily_pnl을 초기화한다."""
+    while True:
+        now = datetime.now(timezone.utc)
+        next_midnight = (now + timedelta(days=1)).replace(
+            hour=0, minute=0, second=0, microsecond=0,
+        )
+        await asyncio.sleep((next_midnight - now).total_seconds())
+        risk.reset_daily()
+
+
 async def main():
     setup_logger(log_level="INFO")
     config = Config()
     risk = RiskManager(config)
 
+    # 기준 잔고를 main에서 한 번만 설정 (경쟁 조건 방지)
+    from src.exchange import BinanceFuturesClient
+    exchange = BinanceFuturesClient(config, symbol=config.symbols[0])
+    balance = await exchange.get_balance()
+    risk.set_base_balance(balance)
+    logger.info(f"기준 잔고 설정: {balance:.2f} USDT")
+
     bots = []
     for symbol in config.symbols:
         bot = TradingBot(config, symbol=symbol, risk=risk)
         bots.append(bot)
 
     logger.info(f"멀티심볼 봇 시작: {config.symbols} ({len(bots)}개 인스턴스)")
-    await asyncio.gather(*[bot.run() for bot in bots])
+    await asyncio.gather(
+        *[bot.run() for bot in bots],
+        _daily_reset_loop(risk),
+    )
 
 
 if __name__ == "__main__":