fix(authentik): pin chart 2026.5.2, grant_types allowlist, portal redirect URI

- Pin the helm-controller chart version (unset = silent latest upgrades) and
  move the image tag under global.image per the 2026.5 chart layout.
- Authentik 2026.5 enforces a per-provider grant_types allowlist; empty list
  rejected every authorize request. Allow authorization_code + refresh_token
  for portal and operator providers.
- Fix the portal redirect URI to the nuxt-oidc-auth callback path.
- Serve the auth ingress on :80 with a per-router HTTPS redirect so the
  cert-manager HTTP-01 solver keeps working.

infrastructure/production/fleet/authentik/blueprints/operator-application.yaml

@@ -44,6 +44,12 @@ entries:
         - !Find [authentik_providers_oauth2.scopemapping, [managed, "goauthentik.io/providers/oauth2/scope-profile"]]
       sub_mode: hashed_user_id
       issuer_mode: per_provider
+      # Authentik 2026.5+ enforces a per-provider grant_types allowlist; an empty
+      # list rejects every authorize request ("Invalid grant_type for provider").
+      # authorization_code = login; refresh_token = offline_access silent refresh.
+      grant_types:
+        - authorization_code
+        - refresh_token
 
   - id: operator-application
     model: authentik_core.application