feat(chart): add @hm-design/chart package with Bar, Line, Donut, Pie, Radar, Area and Radial charts

- new workspace package packages/chart (shadcn/ui Chart + Recharts, HM Theme tokens), examples entry with sample data
- Storybook Chart group (src/chart), consumer example (examples/chart), build:chart / build:chart-example scripts
- README rewritten as the AI usage guide (install, CSS wiring, chart selection, data rules, verification)
- docs: package count/list, Submodule guide (chart workspace, React dedupe), shared AI_GUIDE row, MAINTAINING, story inventory

packages/chart/src/index.ts

@@ -0,0 +1,36 @@
+import "./chart.css"
+
+// shadcn/ui Chart primitives (official source) for custom Recharts compositions.
+export {
+  ChartContainer,
+  ChartTooltip,
+  ChartTooltipContent,
+  ChartLegend,
+  ChartLegendContent,
+  ChartStyle,
+} from "./components/chart"
+export type { ChartConfig } from "./components/chart"
+
+// Ready-made HM charts. Sample data lives in the separate "@hm-design/chart/examples" entry.
+export { HMBarChart } from "./components/bar-chart"
+export type { HMBarChartProps } from "./components/bar-chart"
+export { HMHorizontalBarChart } from "./components/horizontal-bar-chart"
+export type { HMHorizontalBarChartProps } from "./components/horizontal-bar-chart"
+export { HMSignedBarChart } from "./components/signed-bar-chart"
+export type { HMSignedBarChartProps } from "./components/signed-bar-chart"
+export { HMLineChart } from "./components/line-chart"
+export type { HMLineChartProps } from "./components/line-chart"
+export { HMDonutChart } from "./components/donut-chart"
+export type { HMDonutChartProps, HMDonutDatum } from "./components/donut-chart"
+export { chartColors } from "./components/series"
+export type { ChartSeries } from "./components/series"
+
+export { HMPieChart, HMStackedPieChart } from "./components/pie-chart"
+export type { HMPieChartProps, HMPieRing, HMStackedPieChartProps } from "./components/pie-chart"
+export { HMRadarChart } from "./components/radar-chart"
+export type { HMRadarChartProps } from "./components/radar-chart"
+export { HMAreaChart } from "./components/area-chart"
+export type { HMAreaChartProps } from "./components/area-chart"
+
+export { HMRadialBarChart, HMRadialMeterChart, HMRadialStackedChart } from "./components/radial-chart"
+export type { HMRadialBarChartProps, HMRadialMeterChartProps, HMRadialStackedChartProps } from "./components/radial-chart"