/// SVG rendering components for charts
/// Axis rendering primitives (ticks, labels, lines)
/// Tooltip specific for bar charts (categorical hit-testing)
/// Tooltip specific for box plots and violin charts
/// Tooltip specific for financial candlestick charts
/// Vertical color bar (gradient + tick labels) for continuous color maps
/// Empty state message component for data validation errors
/// Background grid lines rendering
/// Tooltip for heatmap cells (row/col/value)
/// Chart legend rendering component
/// Selection overlays and crosshairs
/// Tooltip specific for radar (spider) charts
/// Tooltip for Sankey diagram nodes and links
/// General-purpose cartesian tooltip (line, scatter, area)
/// Tooltip specific for waterfall charts