feat: daily CNPG Option A backup shell activity (RAILIANCE-WP-0016)

Add cnpg_option_a_backup resolver, disabled ActivityDefinition, ESO
manifest, worker kubeconfig hostPath, databases RBAC, and unit tests.
Enable after ESO token re-mint and host kubeconfig wiring.

k8s/railiance/26-worker-cnpg-backup-rbac.yaml

@@ -0,0 +1,38 @@
+# Optional in-cluster RBAC if using service-account kubeconfig for railiance01
+# databases dumps (alternative to host kubeconfig admin). Prefer host kubeconfig
+# with limited certs for multi-cluster; this Role covers same-cluster exec.
+apiVersion: rbac.authorization.k8s.io/v1
+kind: Role
+metadata:
+  name: actcore-cnpg-logical-backup
+  namespace: databases
+  labels:
+    app.kubernetes.io/part-of: activity-core
+    railiance.apps/backup-lane: option-a
+rules:
+  - apiGroups: [""]
+    resources: ["pods"]
+    verbs: ["get", "list"]
+  - apiGroups: [""]
+    resources: ["pods/exec"]
+    verbs: ["create"]
+  - apiGroups: [""]
+    resources: ["configmaps"]
+    verbs: ["get", "create", "update", "patch"]
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: RoleBinding
+metadata:
+  name: actcore-cnpg-logical-backup
+  namespace: databases
+  labels:
+    app.kubernetes.io/part-of: activity-core
+    railiance.apps/backup-lane: option-a
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: Role
+  name: actcore-cnpg-logical-backup
+subjects:
+  - kind: ServiceAccount
+    name: default
+    namespace: activity-core