Population BarChart (React & D3)
This example displays the ten most populous countries as a horizontal bar chart, with each bar’s length proportional to its 2020 population estimate. The visualization loads CSV data from a GitHub gist using `d3.csv` and renders an SVG through React components. Scales are constructed with `d3.scaleBand` for the categorical country axis and `d3.scaleLinear` for the continuous population axis, while gridlines and axis ticks are generated via `xScale.ticks()`. The chart updates reactively as data arrives asynchronously.