Function run_hosted_engine_game 

pub fn run_hosted_engine_game(
    game_id: String,
    player_names: Vec<String>,
    decks: Vec<Deck>,
    commander_names: Vec<Option<String>>,
    local_player_index: Option<usize>,
    starting_life: i32,
    remote_prompt_tx: Sender<(usize, AgentMessage)>,
    remote_response_rxs: Vec<(usize, Receiver<ClientToServerMessage>)>,
    game_over_tx: Sender<HostedGameOver>,
) -> Result<(), String>