Interactive draggable chart

### Description

I’d love to have a chart component where users can drag data points directly on the chart to update their values in real time. This would be extremely useful for calibration tasks, “what-if” analyses, and general experimentation with data.

As a reference, the [chartjs-plugin-dragdata](https://github.com/artus9033/chartjs-plugin-dragdata) project demonstrates how this can be done in Chart.js.

### Have you provided an initial effort estimate for this issue?

I am no FlowFuse team member