feat(garage,authentik): console multi-domain + standalone proxy outpost

Two related additions for gating a cross-host service (garage WebUI on a
storage host) behind authentik without breaking on TLS or X-Forwarded-Host:

garage role:
- Add garage_webui_domains (list), mirroring garage_s3_domains. The
  console router now accepts every entry, so a DMZ reverseproxy can use a
  backend_host whose cert SAN matches an internal *.int.* name instead of
  connecting by IP (which fails acme cert verification). Defaults to the
  single garage_webui_domain so existing inventories are unaffected.

authentik_outpost_proxy role (new):
- Standalone proxy (ForwardAuth) outpost, modelled on authentik_outpost_ldap.
  Co-locate it with the protected service so the ForwardAuth subrequest
  reaches authentik over the local docker network. The embedded outpost
  only works for services on the authentik host: a cross-host subrequest
  routed through an extra reverse-proxy hop arrives with a polluted
  X-Forwarded-Host (port/comma-appended), which the outpost no longer
  matches against the provider's external_host (404).

roles/authentik_outpost_proxy/README.md

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+# authentik_outpost_proxy
+
+Deploys an [authentik](https://goauthentik.io) proxy (ForwardAuth)
+outpost via Docker Compose. The outpost serves the
+`/outpost.goauthentik.io/auth/*` endpoints locally, so a Traefik
+`ForwardAuth` middleware on the same host can gate services behind
+authentik without routing the auth subrequest through additional reverse
+proxies.
+
+Use this when the protected service runs on a **different host** than the
+authentik server: the embedded outpost only works for services co-located
+with authentik (the subrequest must reach it without an intermediate proxy
+mangling `X-Forwarded-Host`). Co-locating a proxy outpost with the service
+keeps the ForwardAuth subrequest on the local docker network.
+
+The outpost connects back to an authentik server using an outpost token
+issued in the authentik admin interface (register the outpost there and
+assign the proxy providers it should serve). The image version must match
+the authentik server version.
+
+## Requirements
+
+- Docker and Docker Compose on the target host (e.g. via
+  `digitalboard.core.base`)
+- Ansible collection: `community.docker`
+- An authentik proxy outpost registered on the server, with the proxy
+  providers for the protected services assigned to it.
+
+## Role variables
+
+| Variable | Default | Description |
+| --- | --- | --- |
+| `authentik_outpost_proxy_image` | `ghcr.io/goauthentik/proxy:2026.2.2` | Outpost image (match the server version). |
+| `authentik_outpost_proxy_host` | `https://authentik.local.test` | URL of the authentik server. |
+| `authentik_outpost_proxy_token` | `changeme` | Outpost token — **override this**. |
+| `authentik_outpost_proxy_insecure` | `"true"` | Skip TLS verification toward the authentik server. |
+| `authentik_outpost_proxy_network` | `proxy` | Docker network the local Traefik routers and this outpost share. |
+| `authentik_outpost_proxy_extra_hosts` | `[]` | Extra `host:ip` entries for in-container DNS. |
+
+The local ForwardAuth middleware then points at the container over the
+shared network, e.g.
+`http://authentik-outpost-proxy-proxy-1:9000/outpost.goauthentik.io/auth/traefik`.
+
+## Example
+
+```yaml
+- hosts: storage
+  become: true
+  roles:
+    - role: digitalboard.core.authentik_outpost_proxy
+      vars:
+        authentik_outpost_proxy_host: "https://auth.example.com"
+        authentik_outpost_proxy_token: "{{ vault_authentik_proxy_outpost_token }}"
+```
+
+## License
+
+MIT-0