fix(plugin-rss): fix dependency issues

[chenjiahan]

Summary

• Add the missing @rspress/shared dependency.
• Import runtime methods from rspress/runtime instead of @rspress/runtime.
• Remove @types/react from peerDependencies.

Checklist

• I have added changeset via pnpm run change.
• I have updated the documentation.
• I have added tests to cover my changes.

[netlify]

✅ Deploy Preview for aquamarine-blini-95325f ready!

Name	Link
🔨 Latest commit	819586b
🔍 Latest deploy log	https://app.netlify.com/sites/aquamarine-blini-95325f/deploys/660fcac74f7d5b0007271900
😎 Deploy Preview	https://deploy-preview-908--aquamarine-blini-95325f.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.
Lighthouse	1 paths audited Performance: 91 (🟢 up 5 from production) Accessibility: 97 (no change from production) Best Practices: 100 (no change from production) SEO: 92 (no change from production) PWA: - View the detailed breakdown and full score reports

---

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