feat: deploy Immich with Authentik OIDC, rock as admin

Self-hosted photo backup (Google Photos replacement) - raw manifests,
no Helm chart, self-contained under k8s/apps/immich including its own
CNPG Postgres. Media PVC shares the cp-3 HDD 2TB/2TB with
paperless-media.

Postgres is pg18, not this repo's usual 16.2: CNPG's official pgvector
extension image (ghcr.io/cloudnative-pg/pgvector) is only published
for pg18, loaded via CNPG's ImageVolume extension mechanism (operator
1.30.0 / k8s 1.36.1 both support it). Immich auto-manages CREATE
EXTENSION itself at startup.

OIDC via a new "immich_role" Authentik scope mapping (homelab-admins/
immich-admins -> "admin" claim, else "user"), consumed by Immich's
OAuth roleClaim setting which re-syncs isAdmin on every login - more
reliable than Immich's racy first-user-is-admin fallback. Config
composed into an immich-oidc Secret and mounted as IMMICH_CONFIG_FILE,
matching the paperless-oidc pattern. k8s RBAC (immich-operator Role +
oidc:immich-admins binding) mirrors paperless/rbac.yaml.

immich namespace pre-created in k8s/infra/databases/namespaces.yaml
(not just immich's own CreateNamespace=true) since the iam PostSync
job's RoleBinding needs it to exist before wave 8.

k8s/apps/immich/rbac.yaml

@@ -0,0 +1,35 @@
+# Scoped operator access for immich-admins: restart/config-edit rights on
+# just this service's own resources, nothing CNPG-managed (immich-db-*) or
+# provisioning-managed (immich-oidc). Same pattern as
+# k8s/apps/paperless/rbac.yaml. Inert until kube-apiserver's OIDC wiring
+# lands (--oidc-groups-claim=groups, --oidc-groups-prefix=oidc:).
+apiVersion: rbac.authorization.k8s.io/v1
+kind: Role
+metadata:
+  name: immich-operator
+rules:
+  - apiGroups: ["apps"]
+    resources: ["deployments"]
+    resourceNames: ["immich-server", "immich-machine-learning"]
+    verbs: ["get", "list", "watch", "update", "patch"]
+  - apiGroups: [""]
+    resources: ["configmaps"]
+    resourceNames: ["immich-config"]
+    verbs: ["get", "list", "watch", "update", "patch"]
+  - apiGroups: [""]
+    resources: ["secrets"]
+    resourceNames: ["immich-oidc"]
+    verbs: ["get", "list", "watch", "update", "patch"]
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: RoleBinding
+metadata:
+  name: immich-admins-binding
+subjects:
+  - kind: Group
+    name: "oidc:immich-admins"
+    apiGroup: rbac.authorization.k8s.io
+roleRef:
+  kind: Role
+  name: immich-operator
+  apiGroup: rbac.authorization.k8s.io