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/pagesarchive/extract.go

@@ -124,7 +124,7 @@ func extractEntries(entries []Entry, destDir string, opts ExtractOptions) error
 		appendMeasuredFile(measured, normalizedPath, actual)
 	}
 	if measured.fileCount == 0 {
-		return fmt.Errorf("pages package is empty")
+		return errors.New("pages package is empty")
 	}
 	return nil
 }
@@ -139,7 +139,7 @@ func extractTarFamilyAt(ra io.ReaderAt, size int64, format Format, destDir strin
 		return err
 	}
 	if firstPass.fileCount == 0 {
-		return fmt.Errorf("pages package is empty")
+		return errors.New("pages package is empty")
 	}
 	commonPrefix := ""
 	if opts.StripCommonRoot {
@@ -162,7 +162,7 @@ func extractTarFamilyAt(ra io.ReaderAt, size int64, format Format, destDir strin
 		return extractErr
 	}
 	if secondPass.fileCount != firstPass.fileCount || secondPass.totalSize != firstPass.totalSize {
-		return fmt.Errorf("pages tar package changed between validation and extraction")
+		return errors.New("pages tar package changed between validation and extraction")
 	}
 	return nil
 }