优化结构

internal/service/system/export_excel_value_test.go

@@ -0,0 +1,10 @@
+package system
+
+import "testing"
+
+func TestExportCellValuePreservesNumericText(t *testing.T) {
+	value, ok := exportCellValue("007").(string)
+	if !ok || value != "007" {
+		t.Fatalf("exportCellValue() = %#v, want string 007", exportCellValue("007"))
+	}
+}