Create interactive 'd3.js' visualizations from R with built-in statistical transforms. Computes confidence intervals, regression fits, LOESS smoothing, moving averages, error bars, and uncertainty visualizations (quantile dot plots and fan charts) in R and renders them as composable chart layers via 'htmlwidgets'. Supports 36 chart types including boxplots, violin plots, Q-Q diagnostic plots, calendar heatmaps, survival curves, and group comparisons with pairwise significance testing. Also provides a machine-readable chart specification schema with validators so that large language model agents can author and verify charts. Works in 'RStudio', 'Shiny', and 'R Markdown'.