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/ldap-gateway.yaml

@@ -0,0 +1,47 @@
+---
+apiVersion: gateway.networking.k8s.io/v1
+kind: Gateway
+metadata:
+  labels:
+    traefik.io/instance: internal
+  annotations:
+    cert-manager.io/cluster-issuer: vault-issuer
+    cert-manager.io/common-name: ldap.k8s.syd1.au.unkin.net
+    cert-manager.io/private-key-size: "4096"
+  name: authentik-ldap
+  namespace: authentik
+spec:
+  gatewayClassName: traefik-internal
+  listeners:
+    - allowedRoutes:
+        namespaces:
+          from: Same
+      hostname: ldap.k8s.syd1.au.unkin.net
+      name: ldaps-internal
+      port: 636
+      protocol: TLS
+      tls:
+        mode: Passthrough
+    - allowedRoutes:
+        namespaces:
+          from: Same
+      hostname: ldap.main.unkin.net
+      name: ldaps-main
+      port: 636
+      protocol: TLS
+      tls:
+        mode: Passthrough
+    - allowedRoutes:
+        namespaces:
+          from: Same
+      hostname: ldap.k8s.syd1.au.unkin.net
+      name: http-dns
+      port: 80
+      protocol: HTTP
+    - allowedRoutes:
+        namespaces:
+          from: Same
+      hostname: ldap.main.unkin.net
+      name: http-dns-main
+      port: 80
+      protocol: HTTP