Function access_with_password 

async fn access_with_password(
    client: &PasswordManagerClient,
    send_id: &str,
    access_key: &SendAccessKey,
    inputs: &ReceiveInputs,
) -> Result<String>

Password-protected Sends: resolve the password from flags/env/file/prompt, run it through the same PBKDF2 recipe bw send create --password used, and exchange it for a token.