feat: support restart build in build watch mode

[9aoy]

Summary

support restart build in build watch mode when config changed.

$ rsbuild build -w

Related Links

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).

[netlify]

✅ Deploy Preview for rsbuild ready!

Name	Link
🔨 Latest commit	13c4f42
🔍 Latest deploy log	https://app.netlify.com/sites/rsbuild/deploys/6735debc82278a00087d1b91
😎 Deploy Preview	https://deploy-preview-3974--rsbuild.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.
Lighthouse	1 paths audited Performance: 83 (🟢 up 12 from production) Accessibility: 97 (no change from production) Best Practices: 100 (no change from production) SEO: 100 (no change from production) PWA: 60 (no change from production) View the detailed breakdown and full score reports

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[chenjiahan]

Can we add a test case?