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/handler/knowledge_image_test.go

@@ -77,3 +77,16 @@ func TestBuildObjectKeyPrefix(t *testing.T) {
 		t.Errorf("key/ext 应以 .jpg 结尾: %s / %s", key, ext)
 	}
 }
+
+func TestBuildDataKey(t *testing.T) {
+	key, ext, err := buildDataKey("spectrum", "a.CSV")
+	if err != nil {
+		t.Fatalf("buildDataKey 失败: %v", err)
+	}
+	if !strings.HasPrefix(key, "spectrum/") || !strings.HasSuffix(key, ".csv") {
+		t.Errorf("key 不正确: %s", key)
+	}
+	if ext != ".csv" {
+		t.Errorf("ext = %s, want .csv", ext)
+	}
+}