The forge's `/metrics` is published behind the gateway and denied to
everyone, waiting on a client to allow. This is that client.
An audience is a URL: authelia validates a bearer token against the
address being requested, and a client may only request an audience it is
registered for, so registration is the authorisation. The URLs are owned
by the services that publish them while audiences attach to one client,
so services contribute to a list and this module builds the single entry
— the `gateway.localNames` split, forced here by client definitions
concatenating rather than merging into a shared entry.
The access-control rule asks the client list whether the collector is
registered rather than re-deriving the conditions that register it. The
two drifting is not a build failure: authelia refuses a rule naming an
unknown client in its startup validator, so SSO fails to restart.