docs: replace placeholder site URL and view-only edit link

## What happened
The current website configuration in website/docusaurus.config.js still contains:

- url: https://your-docusaurus-test-site.com
- docs editUrl: https://github.com/aws-samples/eks-workshop-developers/tree/main/website

The production site URL is a Docusaurus placeholder, and the docs editUrl uses GitHub's tree view rather than the edit route.

## Why it matters
The placeholder URL can produce incorrect canonical/OpenGraph metadata and deployment links. The “Edit this page” action sends contributors to a read-only tree page, so they cannot immediately propose a documentation change.

## Suggested fix
Set url to the actual deployed workshop URL and change the docs editUrl to the repository's edit route, then verify canonical metadata and one generated edit link in the published site.

Open website/docusaurus.config.js and inspect the current site URL and docs editUrl settings. First identify the actual deployed workshop URL from the repository or deployment configuration, then update the URL and use the repository's edit route. Verify the canonical metadata and one generated “Edit this page” link on the published site.

Written by the indexing model from the issue text.