Fix Jenkinsfile: add missing BASE_IMAGE parameter

Jenkinsfile

@@ -10,6 +10,7 @@ pipeline {
         string(name: 'IMAGE_TAG', defaultValue: 'v0.19.0', description: 'Docker image tag')
         string(name: 'GIT_REPO', defaultValue: 'https://sweetapi.com/biondizzle/vllm-deepseek-v32-mtp.git', description: 'Git repository URL (optional, uses workspace if empty)')
         string(name: 'GIT_BRANCH', defaultValue: 'master', description: 'Git branch to build')
+        string(name: 'BASE_IMAGE', defaultValue: 'vllm/vllm-openai:v0.19.0', description: 'Base Docker image')
     }
 
     stages {
@@ -30,7 +31,7 @@ pipeline {
                     docker.withRegistry("https://${REGISTRY}", 'ATL_VCR_VLLM') {
                         sh """
                             docker build \
-                                --build-arg BASE_IMAGE=${BASE_IMAGE} \
+                                --build-arg BASE_IMAGE=${params.BASE_IMAGE} \
                                 -t ${REGISTRY}/${IMAGE_NAME}:${params.IMAGE_TAG} \
                                 .
                         """