Function render_dashboard 

pub fn render_dashboard(
    frame: &mut Frame<'_>,
    rows: &[AgentRow],
    status_line: &str,
    broker_log: &BrokerLog,
)

Renders one frame of the dashboard TUI to the given Frame.

Public wrapper around the internal draw_frame so integration tests can drive a real frame with ratatui::backend::TestBackend and assert against the resulting buffer.