fix: keep ESQuery highlights aligned while typing

[Pixel998]

Prerequisites checklist

• I have read the contributing guidelines.

AI acknowledgment

• I did not use AI to generate this PR.
• (If the above is not checked) I have reviewed the AI-generated content before submitting.

What is the purpose of this pull request?

This PR fixes a bug where ESQuery-highlighted ranges drift left while typing in the editor, then snap back after the debounced AST update finishes.

Steps to reproduce

1. Enter Literal in the ESQuery Selector input.
2. Confirm a literal in the editor is highlighted.
3. Move the cursor to a position before that literal.
4. Start typing in the editor.
5. Notice the highlight shifts left as you type.
6. Stop typing and wait for the debounce to complete.
7. Notice the highlight returns to the correct literal.

What changes did you make? (Give an overview)

• Remapped CodeMirror highlight decorations through document changes so the existing highlight stays anchored during live edits
• Added an e2e regression test.

Related Issues

Is there anything you'd like reviewers to focus on?

[netlify]

✅ Deploy Preview for eslint-code-explorer ready!

Name	Link
🔨 Latest commit	7a29ab7
🔍 Latest deploy log	https://app.netlify.com/projects/eslint-code-explorer/deploys/69c406bd095a160008124c29
😎 Deploy Preview	https://deploy-preview-365--eslint-code-explorer.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 project configuration.

[DMartens]

Changes LGTM, thanks. Leaving it open for a day if someone else wants to review it.

[amareshsm]

LGTM.