feat: 多检测方式推荐引擎（#20，设备/紧急/操作者/成本偏好）

server-go/internal/service/detection_recommend_test.go

@@ -0,0 +1,64 @@
+package service
+
+import "testing"
+
+func TestRecommendMethodNoDevices(t *testing.T) {
+	got := RecommendMethod(DetectionRecommendInput{})
+	if len(got) != 0 {
+		t.Errorf("无可用设备应返回空，实际 %+v", got)
+	}
+}
+
+func TestRecommendMethodLowCost(t *testing.T) {
+	got := RecommendMethod(DetectionRecommendInput{
+		HasLamp: true, HasSers: true, HasQPCR: true,
+		CostPreference: "low_cost",
+	})
+	if len(got) == 0 || got[0].Method != "lamp" {
+		t.Errorf("低成本偏好应首选 LAMP，实际 %+v", got)
+	}
+}
+
+func TestRecommendMethodFastest(t *testing.T) {
+	got := RecommendMethod(DetectionRecommendInput{
+		HasLamp: true, HasSers: true, HasQPCR: true,
+		CostPreference: "fastest",
+	})
+	if len(got) == 0 || got[0].Method != "sers" {
+		t.Errorf("最快偏好应首选 SERS，实际 %+v", got)
+	}
+}
+
+func TestRecommendMethodUrgentNoSERS(t *testing.T) {
+	got := RecommendMethod(DetectionRecommendInput{
+		HasLamp: true, HasQPCR: true,
+		Urgency: "urgent",
+	})
+	if len(got) == 0 || got[0].Method != "lamp" {
+		t.Errorf("紧急且无 SERS 应首选 LAMP，实际 %+v", got)
+	}
+}
+
+func TestRecommendMethodNoviceAvoidsQPCR(t *testing.T) {
+	got := RecommendMethod(DetectionRecommendInput{
+		HasLamp: true, HasSers: true, HasQPCR: true,
+		OperatorLevel: "novice",
+	})
+	if len(got) == 0 {
+		t.Fatal("应有推荐")
+	}
+	if got[len(got)-1].Method == "qpcr" {
+		// qPCR 难度高，新手应排在最后（除非仅此可选）
+	}
+	// 至少 qPCR 不应排第一
+	if got[0].Method == "qpcr" {
+		t.Errorf("新手不应首选 qPCR，实际 %+v", got)
+	}
+}
+
+func TestRecommendMethodOnlyHyperspectral(t *testing.T) {
+	got := RecommendMethod(DetectionRecommendInput{HasHyperspectral: true})
+	if len(got) != 1 || got[0].Method != "hyperspectral" {
+		t.Errorf("仅有高光谱时应推荐且标注待验证，实际 %+v", got)
+	}
+}