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>

tests/test_exchange.py

@@ -1,3 +1,4 @@
+import threading
 import pytest
 from unittest.mock import AsyncMock, MagicMock, patch
 from src.exchange import BinanceFuturesClient
@@ -25,6 +26,7 @@ def client():
     c.symbol = config.symbol
     c._qty_precision = 1
     c._price_precision = 4
+    c._api_lock = threading.Lock()
     return c
 
 
@@ -43,6 +45,7 @@ def exchange():
     c.client = MagicMock()
     c._qty_precision = 1
     c._price_precision = 4
+    c._api_lock = threading.Lock()
     return c