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}

pkg/render/openresty/status_codes.go

@@ -4,6 +4,7 @@
 package openresty
 
 import (
+	"errors"
 	"fmt"
 	"sort"
 	"strconv"
@@ -22,7 +23,7 @@ const (
 func ParseStatusCodeTag(tag string) (lo, hi int, err error) {
 	tag = strings.TrimSpace(tag)
 	if tag == "" {
-		return 0, 0, fmt.Errorf("状态码标签不能为空")
+		return 0, 0, errors.New("状态码标签不能为空")
 	}
 	if before, after, ok := strings.Cut(tag, "-"); ok {
 		lo, err = strconv.Atoi(before)