feat(dashboard): migrate to Vite and React 18

[vijay8i]

Summary

• adopt a Vite root entrypoint, reuse the legacy alias map, and serve static assets from src/web/assets with JSX-friendly bundling
• update the dashboard dependencies and tooling for React 18, Tailwind 3, and modern Stylelint/PostCSS configs
• convert Jest transforms to .cjs, load Testing Library matchers in setup, await async userEvent calls, and rename React sources to .jsx

Testing

• npm test
• npm run build

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https://chatgpt.com/codex/tasks/task_b_682d55d1906c832c9567babb4bbb9b25