fix(website): migrate Pages URLs to OWASP

[ritiksah141]

Summary

• migrate the Astro site, canonical metadata, sitemap, RSS, robots, CMS, repository links, badges, and clone instructions from the retired openshield-org identity to OWASP
• update Decap CMS to target OWASP/openshield
• publish the official OWASP Pages artifact only from the release-controlled main branch while retaining PR validation for dev and main
• fail website verification if openshield-org is reintroduced into website source files

Verification

• npm run check --prefix website
• 14 Astro pages built and verified with CMS disabled and enabled
• rendered canonical, Open Graph, structured-data, robots, RSS, and sitemap URLs use https://owasp.github.io/openshield/
• rendered website contains no openshield-org references
• workflow assertion confirms only refs/heads/main can upload and deploy the Pages artifact
• repository pre-commit checks passed

Required administrator action

This PR does not change repository administration settings. An OWASP repository administrator must set Settings > Pages > Build and deployment > Source to GitHub Actions, then rerun the website workflow from main. Until that is done, actions/deploy-pages will continue failing with HTTP 404 and GitHub will keep serving the legacy main Pages build.

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None

[Vishnu2707]

Approved, LGTM!