fix: generate npm auth via PowerShell to bypass Jenkins Groovy sandbox

Jenkinsfile

@@ -67,11 +67,10 @@ pipeline {
         stage('Publish to Nexus') {
             steps {
                 withCredentials([usernamePassword(credentialsId: 'NEXUS_CREDS', passwordVariable: 'NPM_PASS', usernameVariable: 'NPM_USER')]) {
-                    script {
-                        def auth = (NPM_USER + ':' + NPM_PASS).bytes.encodeBase64().toString()
-                        writeFile file: '.npmrc', text: "//nexus.xuqinmin.com/repository/npm-hosted/:_auth=${auth}\n"
-                        bat "npm publish --registry %NEXUS_REGISTRY%"
-                    }
+                    bat """
+                        powershell -NonInteractive -Command "Set-Content .npmrc ('//nexus.xuqinmin.com/repository/npm-hosted/:_auth=' + [Convert]::ToBase64String([Text.Encoding]::ASCII.GetBytes(\$env:NPM_USER + ':' + \$env:NPM_PASS)))"
+                        npm publish --registry %NEXUS_REGISTRY%
+                    """
                 }
             }
             post {