The repository was transferred from the glittercowboy org to gsd-build,
but several files still referenced the old org in URLs. This updates all
repository URL references across READMEs (all languages), package.json,
and the update workflow. Also removes a duplicate language selector in
the main README header.
Files intentionally unchanged:
- CHANGELOG.md (historical entries)
- CODEOWNERS, FUNDING.yml, SECURITY.md (reference @glittercowboy as a
GitHub username/handle, not a repo URL)
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
