perfsprint 18→0：strconv.Itoa/FormatInt/FormatUint/FormatBool 替代 fmt.Sprintf、无动词 fmt.Errorf→errors.New、纯字符串拼接。全部语义等价（已核对 diff）。修正 fixer 遗留的 import 问题（引入 goimports 统一整理）。

Result: {"status":"keep","total_issues":56,"golint_canonicalheader":8,"golint_errname":1,"golint_errorlint":12,"golint_forcetypeassert":3,"golint_gosec":0,"golint_intrange":3,"golint_modernize":5,"golint_nilnil":3,"golint_perfsprint":0,"golint_prealloc":3,"golint_recvcheck":7,"golint_usestdlibvars":3,"golint_wastedassign":7,"golint_total":55,"eslint_problems":1,"eslint_errors":0,"eslint_warnings":1,"tsc_errors":0,"measure_s":47}

internal/apps/openflare/zone/legacy_import.go

@@ -103,7 +103,7 @@ func ImportLegacyTx(ctx context.Context, tx *sql.Tx, postgres bool) (report Impo
 		`), domain).Scan(&existingID, &existingZoneDomain)
 		if scanErr == nil {
 			if existingZoneDomain != root {
-				report.Conflicts = append(report.Conflicts, fmt.Sprintf("%s: global domain conflict", domain))
+				report.Conflicts = append(report.Conflicts, domain+": global domain conflict")
 			} else if item.ProxyRouteID != nil {
 				if _, bindErr := tx.ExecContext(ctx, q(`
 					UPDATE of_zone_domains
@@ -147,7 +147,7 @@ func ImportLegacyTx(ctx context.Context, tx *sql.Tx, postgres bool) (report Impo
 	}
 
 	if len(report.Conflicts) > 0 {
-		return report, fmt.Errorf("legacy data has conflicts")
+		return report, errors.New("legacy data has conflicts")
 	}
 	return report, nil
 }