Add Authentik identity provider deployment

- Helm chart authentik 2026.5.3 with 3 server replicas, 2 worker replicas
- CNPG PostgreSQL cluster (3 instances) with rw and ro poolers (2 instances each)
- Redis with 5Gi persistent storage
- Gateway API: identity.unkin.net and identity.k8s.syd1.au.unkin.net (HTTPS)
- LDAPS via TLSRoute on ldap.k8s.syd1.au.unkin.net and ldap.main.unkin.net
- Multi-SAN TLS via cert-manager gateway integration
- S3 storage via RadosGW (bucket: authentik)
- Vault secrets: postgres-credentials, authentik-credentials, s3-credentials
- Woodpecker ServiceAccount for terraform-authentik CI
- Platform applicationset and project updated

apps/base/authentik/redis-service.yaml

@@ -0,0 +1,17 @@
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: redis
+  namespace: authentik
+spec:
+  internalTrafficPolicy: Cluster
+  ports:
+    - name: redis
+      port: 6379
+      protocol: TCP
+      targetPort: redis
+  selector:
+    app: redis
+  sessionAffinity: None
+  type: ClusterIP