feat(server-go): 分子检测扩展（qPCR Ct 判读/SERS 光谱上传/光谱库，#19）

server-go/internal/model/molecular.go

@@ -0,0 +1,49 @@
+package model
+
+import (
+	"errors"
+	"path/filepath"
+	"strings"
+)
+
+const maxSpectrumSize = 5 << 20 // 5MB
+
+// ValidDetectionMethod 检测方式枚举
+func ValidDetectionMethod(method string) bool {
+	switch method {
+	case "lamp", "qpcr", "sers", "hyperspectral":
+		return true
+	default:
+		return false
+	}
+}
+
+// JudgeQPCR qPCR Ct 值自动判读：任一 Ct < threshold 判阳性，无 Ct 判阴性
+func JudgeQPCR(cts []float64, threshold float64) (string, string) {
+	if threshold <= 0 {
+		threshold = 35
+	}
+	if len(cts) == 0 {
+		return "negative", "未检出 Ct 值，判为阴性"
+	}
+	for _, ct := range cts {
+		if ct < threshold {
+			return "positive", "存在 Ct 值低于阈值，判为阳性"
+		}
+	}
+	return "negative", "全部 Ct 值不低于阈值，判为阴性"
+}
+
+// ValidateSpectrumFile 光谱数据文件校验（csv/txt/json，≤5MB）
+func ValidateSpectrumFile(filename string, size int64) error {
+	if size <= 0 || size > maxSpectrumSize {
+		return errors.New("光谱文件大小需在 1B~5MB 之间")
+	}
+	ext := strings.ToLower(filepath.Ext(filename))
+	switch ext {
+	case ".csv", ".txt", ".json":
+		return nil
+	default:
+		return errors.New("仅支持 csv/txt/json 光谱数据文件")
+	}
+}