Function run_agent_loop 

pub async fn run_agent_loop(
    provider: Arc<dyn Provider>,
    model: &str,
    system_prompt: &str,
    user_prompt: &str,
    tools: Vec<ToolDefinition>,
    registry: Arc<ToolRegistry>,
    max_steps: usize,
    timeout_secs: u64,
    event_tx: Option<Sender<SwarmEvent>>,
    subtask_id: String,
    bus: Option<Arc<AgentBus>>,
    working_dir: Option<PathBuf>,
) -> Result<(String, usize, usize, AgentLoopExit)>