Add Authentik identity provider deployment

- CNPG PostgreSQL cluster (3 instances) with rw and ro poolers (2 instances each)
- Redis with persistent storage
- Gateway API: identity.unkin.net (HTTPS) + LDAPS via TLSRoute on ldap.k8s.syd1.au.unkin.net and ldap.main.unkin.net
- HTTPRoute for external-dns record creation on LDAP hostnames
- Vault secrets: postgres-credentials, authentik-credentials, s3-credentials
- S3 storage via RadosGW
- Helm chart authentik 2026.5.3 with 3 server replicas, 2 worker replicas
- Woodpecker ServiceAccount for terraform-authentik CI
- Platform applicationset and project updated

apps/base/authentik/redis-pvc.yaml

@@ -0,0 +1,13 @@
+---
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: redis-data
+  namespace: authentik
+spec:
+  accessModes:
+    - ReadWriteOnce
+  resources:
+    requests:
+      storage: 5Gi
+  storageClassName: cephrbd-fast-delete