refactor: improve header anchor logic and simplify URL validation

[Simon-He95]

Summary

Related Issue

Checklist

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

[netlify]

✅ Deploy Preview for rspress-v2 ready!

Name	Link
🔨 Latest commit	a93ba82
🔍 Latest deploy log	https://app.netlify.com/sites/rspress-v2/deploys/67e0f70210329d0008f7d2bf
😎 Deploy Preview	https://deploy-preview-1994--rspress-v2.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

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

[netlify]

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

Name	Link
🔨 Latest commit	a93ba82
🔍 Latest deploy log	https://app.netlify.com/sites/aquamarine-blini-95325f/deploys/67e0f7022fba190008acbc57
😎 Deploy Preview	https://deploy-preview-1994--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: 89 (🔴 down 4 from production) Accessibility: 97 (no change from production) Best Practices: 92 (no change from production) SEO: 100 (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.

[SoonIter]

thanks ❤️️