Docs: "Edit this page on GitHub" button

As a user I'd like to have an "edit on GitHub" button on each doc page to suggest documentation improvements quickly.

<img width="757" height="210" alt="Image" src="https://github.com/user-attachments/assets/0dd87ad9-c093-412a-942d-1c14fcb17280" />

VitePress already has a functionality to allow this.