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

.storybook/preview.tsx

@@ -45,6 +45,8 @@ const preview: Preview = {
           ],
           "Patterns",
           ["Data", ["Data Table", "Filter Bar"], "Layout", ["GNB", "LNB", "Dashboard Layout", "Loading Screen"]],
+          "Chart",
+          ["Bar Chart", "Line Chart", "Donut Chart", "Pie Chart", "Radar Chart", "Area Chart", "Radial Chart"],
           "OrgChart",
           ["Overview", "Department Colors", "Full Composition", "Expanded OrgChart"],
           "Center Graphic",