Function render_chart_view 

pub fn render_chart_view(
    area: Rect,
    buf: &mut Buffer,
    modal: &mut ChartModal,
    theme: &Theme,
    render_data: ChartRenderData<'_>,
)

Renders the chart view: title, left sidebar (chart type, x/y inputs+lists, checkboxes), and chart area (no border). When only x is selected (no chart data), x_bounds may be Some((min, max)) from the x column so the x axis shows the proper range.