feat: add Redpanda and wp-deploy-coordinator to Legion

- Redpanda single-node StatefulSet in platform namespace
- wp-coordinator deployment consuming wp.deploy topic
- RBAC for coordinator to exec into harmonic-wordpress pods
- R2 credentials via ExternalSecret (no SSH key needed on coordinator)
- Sites config as ConfigMap — add new WP sites without code changes

servers/legion/k8s/redpanda/pvc.yaml

@@ -0,0 +1,12 @@
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: redpanda-data
+  namespace: platform
+spec:
+  storageClassName: local-path
+  accessModes:
+    - ReadWriteOnce
+  resources:
+    requests:
+      storage: 10Gi