feat: add homelab-wide Authentik RBAC model and k8s OIDC auth wiring

Adds permissions claim + per-service admin groups in Authentik, scoped
Role/RoleBinding per service, public PKCE kubernetes OAuth2 client, and
kube-apiserver OIDC extraArgs. Also fixes paperless OIDC signup permissions
via adapter override and adds CoreDNS rewrite for authentik.riotpiao.com.

k8s/infra/rbac/minio-operator-role.yaml

@@ -0,0 +1,33 @@
+# Scoped operator access for minio-admins: the tenant StatefulSet + root
+# creds only - NOT the minio-operator Deployment (shared cluster-wide infra;
+# editing it risks breaking MinIO for every tenant, not just this one).
+# minio-oidc/sts-tls stay excluded (security-managed, not app config). Inert
+# until kube-apiserver's OIDC wiring lands.
+apiVersion: rbac.authorization.k8s.io/v1
+kind: Role
+metadata:
+  name: minio-operator-admin
+  namespace: storage
+rules:
+  - apiGroups: ["apps"]
+    resources: ["statefulsets"]
+    resourceNames: ["minio-cluster-az-a"]
+    verbs: ["get", "list", "watch", "update", "patch"]
+  - apiGroups: [""]
+    resources: ["secrets"]
+    resourceNames: ["minio-creds"]
+    verbs: ["get", "list", "watch", "update", "patch"]
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: RoleBinding
+metadata:
+  name: minio-admins-binding
+  namespace: storage
+subjects:
+  - kind: Group
+    name: "oidc:minio-admins"
+    apiGroup: rbac.authorization.k8s.io
+roleRef:
+  kind: Role
+  name: minio-operator-admin
+  apiGroup: rbac.authorization.k8s.io