Feature Request: Allow rendering a custom component at the start of the chart

[gromspys]

Currently, the chart only supports initialSpacing to add empty space before the first data point. It would be great to have an option to render a custom component in that area.

For example, if an app limits historical data for non-logged-in users, we might want to show a message like:

“Login to see more historical data”

This message should appear before the first data point and scroll together with the chart.

Proposed API

renderStartComponent?: () => ReactNode;

Example Usage

<LineChart
  data={data}
  renderStartComponent={() => (
    <View style={{ alignItems: 'center', justifyContent: 'center', width: 120 }}>
      <Text style={{ color: 'gray' }}>Login to see more data</Text>
    </View>
  )}
/>

Expected Behavior

• The returned component appears at the start of the chart content area.
• It scrolls horizontally with the chart (like part of the timeline).
• initialSpacing can still be used for fine-tuning positioning.

Why It’s Useful

• Improves UX for gated or premium data views.
• Avoids hacks like fake data points or absolute overlays.
• Increases flexibility for building interactive chart experiences.