Setup Deploy Previews for Pull Requests

[thib3113]

This change sets up a robust deployment system using GitHub Pages.
It switches the deployment method from "GitHub Actions" source to "Deploy from a branch" source, allowing multiple versions (production and PR previews) to coexist on the gh-pages branch.

Key Features:

1. Production: Pushes to main are deployed to the root of the gh-pages branch.
2. Previews: Pull Requests trigger a deployment to a subfolder pr-<number> on the gh-pages branch.
3. Notifications: The PR is automatically commented with the link to the preview.
4. Cleanup: Closing a PR automatically removes its preview folder.

IMPORTANT: After merging this PR (or pushing these changes), you must go to your repository Settings -> Pages and change the Source to "Deploy from a branch". Select the "gh-pages" branch and the "/(root)" folder. (Note: The gh-pages branch will be created automatically by the first run of the workflow).

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PR created automatically by Jules for task 11956946793758481260 started by @thib3113

[google-labs-jules]

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[github-actions]

🚀 Deploy Preview Ready!

Your changes have been deployed to a temporary environment:
https://thib3113.github.io/boks-web-ble/pr-3/index.html

This preview will be updated automatically with new commits.

[github-actions]

🗑️ Deploy Preview Removed

The preview environment has been cleaned up as the PR is closed.