* Move community walkthroughs from README to docs/community
Extract the community walkthroughs section from README.md into its own
docs/community/walkthroughs.md file and replace it with a short summary
linking to the GitHub Pages URL.
* Address review: fix double-See phrasing, add walkthroughs to docs nav
Move the Community Friends section from the main README into a dedicated
docs page at docs/community/friends.md, following the same structure as
the Reference section.
- New: docs/community/friends.md with content from README
- Updated: docs/toc.yml with Community section and Friends entry
- Updated: docs/docfx.json to include community/*.md in content glob
- Updated: README.md to link to the new docs page instead of inline list
