fix: Correct error handling in decision parsing

Changes:
- Updated error handling in `GetFullDecision` and `parseFullDecisionResponse` functions to return the decision object even when an error occurs, improving the clarity of error messages.
This ensures that the decision object is consistently returned, allowing for better debugging and handling of errors in the decision-making process.

decision/engine.go

@@ -109,7 +109,7 @@ func GetFullDecision(ctx *Context, mcpClient *mcp.Client) (*FullDecision, error)
 	// 4. 解析AI响应
 	decision, err := parseFullDecisionResponse(aiResponse, ctx.Account.TotalEquity, ctx.BTCETHLeverage, ctx.AltcoinLeverage)
 	if err != nil {
-		return nil, fmt.Errorf("解析AI响应失败: %w", err)
+		return decision, fmt.Errorf("解析AI响应失败: %w", err)
 	}
 
 	decision.Timestamp = time.Now()
@@ -427,7 +427,7 @@ func parseFullDecisionResponse(aiResponse string, accountEquity float64, btcEthL
 		return &FullDecision{
 			CoTTrace:  cotTrace,
 			Decisions: []Decision{},
-		}, fmt.Errorf("提取决策失败: %w\n\n=== AI思维链分析 ===\n%s", err, cotTrace)
+		}, fmt.Errorf("提取决策失败: %w", err)
 	}
 
 	// 3. 验证决策
@@ -435,7 +435,7 @@ func parseFullDecisionResponse(aiResponse string, accountEquity float64, btcEthL
 		return &FullDecision{
 			CoTTrace:  cotTrace,
 			Decisions: decisions,
-		}, fmt.Errorf("决策验证失败: %w\n\n=== AI思维链分析 ===\n%s", err, cotTrace)
+		}, fmt.Errorf("决策验证失败: %w", err)
 	}
 
 	return &FullDecision{