feat(homarr): complete wiring for landing page deployment

Adds Homarr landing page with Authentik SSO:
- k8s/argocd/apps/60-applications.yaml: multi-source Application (homarr
  chart from homarr-labs + in-repo values), ns dashboard, wave 8
- k8s/bootstrap/ingress/ingress.yaml: homarr.riotpiao.com → dashboard/homarr:3000
- k8s/bootstrap/coredns/coredns-configmap.yaml: rewrite homarr.riotpiao.com
  to ingress controller
- k8s/security/iam/scripts/authentik-provision.py: added 'homarr' to SERVICES
  (generates OAuth provider/app + homarr-oidc secret with client-id/secret)
- k8s/security/iam/rbac-dashboard-rolebinding.yaml: grants authentik-provisioner
  SA access to dashboard ns for secret management
- k8s/security/iam/kustomization.yaml: includes new RoleBinding

Homarr now fully wired:
- Ingress: https://homarr.riotpiao.com
- SSO: redirects to Authentik, login as rock
- Persistence: 5Gi RWO on longhorn-wffc (3-replica HA)
- Tile config: UI-managed (saved to PVC)

k8s/security/iam/scripts/authentik-provision.py

@@ -245,6 +245,14 @@ SERVICES = {
         "launch_url": "https://argocd.riotpiao.com",
         "display_name": "Argo CD",
     },
+    "homarr": {
+        "client_secret_source": ("dashboard", "homarr-oidc", "client-secret"),
+        "generate_if_missing": True,
+        "extra_secret_literals": {"client-id": "homarr"},
+        "redirect_uris": ["https://homarr.riotpiao.com/api/auth/callback/oidc"],
+        "launch_url": "https://homarr.riotpiao.com",
+        "display_name": "Homarr",
+    },
 }
 
 app_pks_for_binding = []