GET /api/nginx/access-lists omits `clients` array without `?expand=clients` — undocumented

When fetching access lists via the API, the clients array is omitted from
the response unless you append ?expand=clients to the request.

Affected endpoints:

• GET /api/nginx/access-lists
• GET /api/nginx/access-lists/{id}

Expected behavior: Either clients is always included, or the API docs
state that ?expand=clients is required to retrieve them.

Actual behavior: Without ?expand=clients, the response includes an empty or
absent clients field even when clients exist. No error is returned.

Observed Impact: A script I wrote to read access lists to check idempotency
saw zero clients and attempted to recreate them on every run.

Request: Document ?expand=clients in the API reference, or include clients
by default.

Tested against v2.14.0.

Begin with the API reference entries for GET /api/nginx/access-lists and GET /api/nginx/access-lists/{id}, checking how the clients field and expand query parameter are described. Done means the reference clearly explains how to retrieve clients, or the chosen response behavior is documented consistently for both endpoints.