fix: add jenkins-deployer service account to pod template

Pod was using the default K8s service account, whose token returns
401 Unauthorized on API calls. All other pipelines specify
jenkins-deployer which has the necessary RBAC binding.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Mbd06b

Jenkinsfile

@@ -52,6 +52,7 @@ pipeline {
 apiVersion: v1
 kind: Pod
 spec:
+  serviceAccount: jenkins-deployer
   nodeSelector:
     node-type: performance
   tolerations: