- Migrated React integration to @vitejs/plugin-react v6 using Oxc for JSX and Fast Refresh, adding an optional Oxc‑based React compiler.
- Removed the built‑in Babel integration; custom Babel transforms now require @rolldown/plugin-babel configured in vite.plugins.
- Compiler memoizes client components, excludes server rendering, defaults to the installed React major version and requires the React compiler runtime.