FEAT(app): add rbac and kubectl for mcp tools

- ServiceAccount for mas pod
- ClusterRole with read-only permissions
- ClusterRoleBinding
- kubectl installed in Docker image
- Now mas can query Kubernetes API!

deploy/k8s/base/deployment.yaml

@@ -15,6 +15,7 @@ spec:
       labels:
         app: mas
     spec:
+      serviceAccountName: mas
       containers:
       - name: mas
         image: gitea0213.kro.kr/bluemayne/mas:latest