Fix: Resolve Trade History data loss and P&L calculation errors

Major fixes:
1. Trade History data loss issue
   - Root cause: Open records outside analysis window caused close matching failures
   - Solution: Pre-populate position state by reading 3x window of historical records
   - Ensures long-term positions (>5 hours) generate correct trade records
2. P&L calculation errors
   - Remove incorrect leverage multiplication from absolute P&L
   - Correct calculation: Futures P&L = quantity × price difference
   - Leverage only affects P&L percentage (relative to margin)
3. Other fixes
   - Break-even trades (pnl=0) no longer misclassified as losses
   - Perfect strategy shows Profit Factor as 999.0 instead of 0.0
   - Expand analysis window from 20 to 100 cycles (5 hours)
Files changed:
- logger/decision_logger.go: Core matching and calculation logic
- api/server.go: API analysis window
- trader/auto_trader.go: AI decision analysis window
Co-Authored-By: tinkle-community <tinklefund@gmail.com>

trader/auto_trader.go

@@ -510,8 +510,9 @@ func (at *AutoTrader) buildTradingContext() (*decision.Context, error) {
 		marginUsedPct = (totalMarginUsed / totalEquity) * 100
 	}
 
-	// 5. 分析历史表现（最近20个周期）
-	performance, err := at.decisionLogger.AnalyzePerformance(20)
+	// 5. 分析历史表现（最近100个周期，避免长期持仓的交易记录丢失）
+	// 假设每3分钟一个周期，100个周期 = 5小时，足够覆盖大部分交易
+	performance, err := at.decisionLogger.AnalyzePerformance(100)
 	if err != nil {
 		log.Printf("⚠️  分析历史表现失败: %v", err)
 		// 不影响主流程，继续执行（但设置performance为nil以避免传递错误数据）