D3 v5 Zoomable Sunburst
A zoomable sunburst diagram displays the hierarchical structure of the Flare data set, visually encoding each category's size through the arc's angular width. The visualization is rendered as SVG via D3 v5, with the root hierarchy partition built using `d3.hierarchy`, `d3.partition`, and the `d3.arc` generator. Clicking a node triggers a smooth animation using D3's `.transition().duration(750)` with `.attrTween` to interpolate arc positions, while fill colors for top-level categories are assigned using a quantized rainbow interpolation via `d3.scaleOrdinal`.