Add comprehensive internationalization coverage to the SEO audit skill,
backed by 40+ sources from Google Search Central, John Mueller, and
authoritative SEO publications.
New section covers:
- Hreflang implementation (placement, reciprocal refs, x-default, scale)
- Canonicalization for multilingual sites (self-referencing, conflict rules)
- International sitemaps (structure, size limits, Next.js caveats)
- Locale URL structure (subdirectories vs ccTLDs, content negotiation)
- Content quality across locales (AI translation stance, thin pages, HCU)
Also adds:
- Multilingual/Multi-Regional site type to Common Issues
- references/international-seo.md with evidence and source URLs
- Version bump to 1.2.0