docs: panel-area link target

[evolkmann]

Description

Add the target option and clarify that absolute URLs are possible (e.g. for external links to analytics, etc.)

Summary of changes

n/a

Reasoning

I wanted to add an external link in the left sidebar menu and the docs do not currently mention this option.

Additional context

n/a

[Copilot]

Pull Request Overview

This PR enhances the documentation for the panel-area extension by adding the target option and clarifying that absolute URLs are supported for the link property. This enables developers to add external links (e.g., to analytics dashboards) in the panel sidebar menu that can open in new tabs.

• Added documentation for the target option to control link behavior
• Clarified that the link property accepts absolute URLs in addition to relative paths

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}