// MoonChart — Pure MoonBit SVG chart generation library
//
// ## Quick Start
//
//   let chart = BarChart::new()
//     .title("Monthly Sales")
//     .x_labels(["Jan", "Feb", "Mar"])
//     .series(Series::new("Product A", [120.0, 200.0, 150.0]))
//   let svg : String = chart.render()
//
// Supports BarChart, LineChart, and PieChart with automatic axis scaling,
// Tableau 10 color palette, and zero dependencies.