Authenticates API requests via a host-app-provided callback.
Extracts a Bearer token or API key from request headers, invokes the
configured :api_authenticate callback, and assigns workspace_id
and auth_context to the connection on success.
Configuration
config :good_analytics, :api_authenticate, {MyApp.Auth, :authenticate_ga_api}The callback must be arity-2: (token, type) where type is :bearer
or :api_key. It must return {:ok, %{workspace_id: uuid, ...}} on
success or {:error, reason} on failure.