Function create_local_proto 

pub fn create_local_proto(
    project_dir: &Path,
    project_name: &str,
    proto_dir: &str,
    template: ProjectTemplateName,
    echo_role: Option<EchoRole>,
) -> Result<()>

Generate a local.proto file with the given package name.

For the echo service role, uses the full EchoService definition so that actr gen can produce EchoHandler / EchoServiceActor traits. For the echo app role and other templates, generates an empty skeleton.