A (transport, url) pair declaring an available interface for an agent.
Wire fields: transport (required — e.g. "JSONRPC", "GRPC", "HTTP+JSON"), url (required).
transport
url
@type t() :: %A2aEngine.Types.AgentInterface{transport: String.t(), url: String.t()}
@spec from_map(map()) :: {:ok, t()} | {:error, term()}
@spec to_map(t()) :: map()