Function exec_flow_with_siblings 

pub async fn exec_flow_with_siblings(
    flow: &FlowDecl,
    args: Vec<(String, Value)>,
    tools: &ToolRegistry,
    tool_ctx: &ToolCtx,
    providers: &ProviderRegistry,
    flows: &HashMap<String, FlowDecl>,
    events: Option<&EventSink>,
    turn_id: Option<TurnId>,
    flow_run_id: Option<FlowRunId>,
    session: Option<Arc<Session>>,
    flow_cancel: CancellationToken,
    safety: Option<&SafetyConfig>,
    source_dir: Option<PathBuf>,
) -> Result<Value, RuntimeError>