Tambah Jenkinsfile untuk pipeline CI/CD

- Menambahkan file Jenkinsfile baru
- Memasukkan tahap-tahap pipeline seperti Checkout dan Build Assets
- Menyertakan konfigurasi environment untuk PHP dan Composer
- Membersihkan workspace setelah pipeline selesai

Jenkinsfile

@@ -0,0 +1,36 @@
+pipeline {
+    agent any
+
+    environment {
+        PHP_VERSION = '8.1'
+        COMPOSER_HOME = "${WORKSPACE}/.composer"
+    }
+
+    stages {
+        stage('Checkout') {
+            steps {
+                checkout scm
+            }
+        }
+
+        stage('Build Assets') {
+            steps {
+                sh "cd /var/www/lpj"
+                sh "npm install"
+                sh "npm run build"
+            }
+        }
+    }
+
+    post {
+        always {
+            cleanWs()
+        }
+        success {
+            echo 'The pipeline has succeeded!'
+        }
+        failure {
+            echo 'The pipeline has failed.'
+        }
+    }
+}