fix: address code review round 2 — 9 issues (2 critical, 3 important, 4 minor)

Critical:
- #2: Add _entry_lock in RiskManager to serialize concurrent entry (balance race)
- #3: Add startTime to get_recent_income + record _entry_time_ms (SYNC PnL fix)

Important:
- #1: Add threading.Lock + _run_api() helper for thread-safe Client access
- #4: Convert reset_daily to async with lock
- #8: Add 24h TTL to exchange_info_cache

Minor:
- #7: Remove duplicate Indicators creation in _open_position (use ATR directly)
- #11: Add input validation for LEVERAGE, MARGIN ratios, ML_THRESHOLD
- #12: Replace hardcoded corr[0]/corr[1] with dict-based dynamic access
- #14: Add fillna(0.0) to LightGBM path for NaN consistency with ONNX

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

src/risk_manager.py

@@ -11,6 +11,7 @@ class RiskManager:
         self.initial_balance: float = 0.0
         self.open_positions: dict[str, str] = {}  # {symbol: side}
         self._lock = asyncio.Lock()
+        self._entry_lock = asyncio.Lock()  # 동시 진입 시 잔고 레이스 방지
 
     async def is_trading_allowed(self) -> bool:
         """일일 최대 손실 초과 시 거래 중단"""
@@ -58,10 +59,11 @@ class RiskManager:
             self.daily_pnl += pnl
             logger.info(f"오늘 누적 PnL: {self.daily_pnl:.4f} USDT")
 
-    def reset_daily(self):
+    async def reset_daily(self):
         """매일 자정 초기화"""
-        self.daily_pnl = 0.0
-        logger.info("일일 PnL 초기화")
+        async with self._lock:
+            self.daily_pnl = 0.0
+            logger.info("일일 PnL 초기화")
 
     def set_base_balance(self, balance: float) -> None:
         """봇 시작 시 기준 잔고 설정"""