fix: update @playwright/test to 1.59.1 and fix e2e tests

[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 updates @playwright/test to 1.59.1 and fixes the e2e tests that became unreliable after the upgrade.

The failing tests were using keyboard-driven select-all and delete behavior inside the CodeMirror editor. After the Playwright update, that interaction no longer behaved consistently across browsers, especially in WebKit, so the default sample code was not always fully replaced before assertions ran.

What changes did you make? (Give an overview)

• Updated @playwright/test to 1.59.1
• Added a shared helper for interacting with the CodeMirror editor in the e2e tests. The affected tests now replace editor contents using fill() instead of relying on Ctrl/Cmd+A followed by Backspace.

Related Issues

#380

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

[netlify]

✅ Deploy Preview for eslint-code-explorer ready!

Name	Link
🔨 Latest commit	934e73e
🔍 Latest deploy log	https://app.netlify.com/projects/eslint-code-explorer/deploys/69d5bff57997a700083f8182
😎 Deploy Preview	https://deploy-preview-381--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.