Add SEO crawl metadata

[fepegar]

[Generated by a coding agent]

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Summary

• Add robots.txt and sitemap.xml for search engine crawl discovery.
• Add JSON-LD SoftwareSourceCode structured data to the landing page.
• Publish the new SEO files in the GitHub Pages artifact.
• Extend the static site checker to verify the SEO files.
• Add a Smokeshow PR preview workflow with a sticky preview comment, modeled after the main TorchIO docs workflow.

Validation

• mise run build
• uv run python scripts/check_site.py --external
• mise run check
• node --check assets/js/main.js
• git diff --check

[Copilot]

Pull request overview

This pull request adds basic SEO crawl-discovery artifacts and structured data so search engines can find and better understand the TorchIO landing page, and extends the repository’s static checks/deploy pipeline to include them.

Changes:

• Add robots.txt and sitemap.xml at the site root for crawl discovery.
• Add JSON-LD SoftwareSourceCode structured data to index.html.
• Update GitHub Pages deployment artifact and extend scripts/check_site.py to verify the SEO files exist and contain canonical URLs.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
sitemap.xml	Adds a minimal sitemap pointing to the canonical homepage URL.
scripts/check_site.py	Adds a new SEO file check and wires it into the existing check runner.
robots.txt	Adds crawler policy and a sitemap directive for discovery.
README.md	Documents the new root-level SEO files in the repository structure section.
index.html	Embeds JSON-LD structured data to improve search engine understanding of the project.
.github/workflows/deploy.yml	Ensures robots.txt and sitemap.xml are included in the Pages artifact.

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