Translate "React Compiler RC" blog post

[smikitky]

No description provided.

[Copilot]

Pull Request Overview

This PR provides a Japanese translation for the "React Compiler RC" blog post.

• Translates the blog card content in src/content/blog/index.md
• Updates the full blog post in src/content/blog/2025/04/21/react-compiler-rc.md with Japanese text maintaining the original technical details

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/content/blog/index.md	Translated blog card text to Japanese
src/content/blog/2025/04/21/react-compiler-rc.md	Entire blog post content is translated to Japanese while preserving original technical content

Comments suppressed due to low confidence (2)

src/content/blog/2025/04/21/react-compiler-rc.md:15

• [nitpick] Review the translation for tone accuracy to ensure it captures the original enthusiasm conveyed in 'The React team is excited to share new updates' for clarity to the Japanese audience.

React チームより新しいお知らせがあります。

src/content/blog/2025/04/21/react-compiler-rc.md:99

• Verify that the translation here maintains the intended technical nuance regarding Next.js support and performance implications, ensuring consistency with the original message.

これらのツールに加えて、[swc](https://swc.rs/) チームの Kang Dongyoon ([@kdy1dev](https://x.com/kdy1dev)) と協力して、React Compiler を swc プラグインとして追加サポートする作業を進めています。この作業はまだ完了していませんが、[Next.js アプリで React Compiler を有効にする](https://nextjs.org/docs/app/api-reference/config/next-config-js/reactCompiler)と、Next.js のビルドパフォーマンスはかなり向上しているはずです。

[smikitky]

ref-in-render validation が何のことなのか分からず訳してしまいました…なんとなく if (someFlagRef.current) return <>...</> else return <>...</> 的な、refがレンダー結果に染み出す使い方のことなんだろうとは思っていますが