ci: Jenkinsfile 추가 (Kubernetes 동적 에이전트, Gitea webhook 연동용)

Jenkinsfile

@@ -0,0 +1,25 @@
+pipeline {
+    agent {
+        kubernetes {
+            yaml '''
+apiVersion: v1
+kind: Pod
+spec:
+  containers:
+  - name: gradle
+    image: eclipse-temurin:21-jdk
+    command: ["sleep"]
+    args: ["99d"]
+'''
+        }
+    }
+    stages {
+        stage('Build') {
+            steps {
+                container('gradle') {
+                    sh 'chmod +x gradlew && ./gradlew build --console=plain'
+                }
+            }
+        }
+    }
+}