feat: migrate from HeroUI v2 to v3

[wingkwong]

Summary

• Migrate from HeroUI v2 to v3, adopting the new CSS-first architecture, compound components, and BEM class system
• Upgrade React 18 to 19, remove framer-motion, @react-aria/visually-hidden, @heroui/use-theme, @heroui/system, and all 40+ individual @heroui/* v2 packages in favor of @heroui/react + @heroui/styles
• Rewrite removed components: Navbar (native HTML + Tailwind + react-router-dom), Snippet/Code (native HTML), theme switch (useSwitch hook replaced with plain button)

Changes by file

File	Change
package.json	Replace 40+ v2 deps with @heroui/react + @heroui/styles RC, upgrade React to v19
src/styles/globals.css	Replace @plugin/@source with @import "@heroui/styles"
src/hero.ts	Deleted (v3 has no Tailwind plugin)
src/provider.tsx	Remove HeroUIProvider (not needed in v3)
src/layouts/default.tsx	Replace Link with plain <a>, color tokens updated (text-default-600 → text-muted, text-primary → text-accent)
src/pages/index.tsx	Use BEM classes (button--primary, button--tertiary) on <a> tags, replace Snippet/Code with native HTML
src/components/navbar.tsx	Full rewrite with native HTML + react-router-dom Link, v3 BEM classes for Kbd and search
src/components/theme-switch.tsx	Replace useSwitch hook with simple <button> using localStorage
src/components/primitives.ts	Update text-default-600 → `text-m

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
vite-template	Ready	Preview, Comment	Mar 21, 2026 4:33pm

[wingkwong]

heroui-cli reads main branch for init command. Convert this PR to draft and reopen once cli supports v3.