@spec await_instance(pid(), atom(), atom()) ::
  {:ok, GenServer.server()} | {:error, term()}

Waits through root initialization/restart and returns its permanent authority.

Returns a specification to start this module under a supervisor.

See Supervisor.

@spec ensure_root(
  GenServer.server(),
  atom(),
  Minga.Extension.Entry.t(),
  GenServer.server(),
  keyword()
) :: {:ok, GenServer.server()} | {:error, term()}

Ensures one root exists and returns its stable Instance server.

@spec existing_authority(GenServer.server(), atom(), keyword()) ::
  {:ok, GenServer.server()} | :absent | {:error, term()}

Locates an existing root authority, synchronizing through Instance registration.

@spec names(
  GenServer.server(),
  keyword()
) :: [atom()]

Returns declared root names without inspecting runtime children.

@spec start_link(keyword()) :: Supervisor.on_start()

Starts the extension root supervisor.

@spec terminate_root(GenServer.server(), atom(), keyword()) :: :ok | {:error, term()}

Terminates the root for a declaration which no longer exists.