feat: show strikethrough on deprecated endpoints in sidebar

[cetevolte]

Elements Default PR Template

In general, make sure you have: (check the boxes to acknowledge you've followed this template)

• [ x] Read CONTRIBUTING.md

Summary

This PR enhances the Table of Contents (sidebar) to visually indicate deprecated API endpoints by applying a strikethrough style to their titles.

Why

Currently, the only way to see if an endpoint is deprecated is to click into its detail view. This change improves visibility and helps developers quickly identify deprecated operations from the sidebar.

Changes

• Propagate the deprecated flag into the TableOfContentsNode data
• Extend TableOfContentsNode type to include a data.deprecated boolean
• Add UI logic to apply line-through style when deprecated is true

Related issue

Implements the idea suggested in an existing issue:

“A suggested solution is for example to strikethrough the text on the sidebar to show that it is deprecated.”

---

Other Available PR Templates:

• Release: https://github.com/stoplightio/elements/compare?template=release.md
  • Read the release section of CONTRIBUTING.md

[cetevolte]

Hi! 👋
This PR addresses the issue with identifying deprecated endpoints in the sidebar by visually striking through the titles of deprecated operations.
The deprecated flag is now extracted from the operation data and passed into the TableOfContentsNode, and the UI adjusts styling accordingly.

[netlify]

✅ Deploy Preview for stoplight-elements-demo ready!

Name	Link
🔨 Latest commit	28cc399
🔍 Latest deploy log	https://app.netlify.com/sites/stoplight-elements-demo/deploys/6821deb3e01c7500089068b9
😎 Deploy Preview	https://deploy-preview-2795--stoplight-elements-demo.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 stoplight-elements ready!

Name	Link
🔨 Latest commit	28cc399
🔍 Latest deploy log	https://app.netlify.com/sites/stoplight-elements/deploys/6821deb32c4fb70008035c55
😎 Deploy Preview	https://deploy-preview-2795--stoplight-elements.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.

[cetevolte]

Hi @Relionnn,
In my local setup ESLint doesn’t show any errors (simple-import-sort/imports passes fine), so I’m not sure what needs to be changed to fix the CI failure.
Let me know if you spot anything specific I should adjust — happy to update it!

Thanks in advance!