Two new Nikkei Asia section sources, built on the same composite
listSelector + validateArticle pattern proven on nikkei-tech:
- nikkei-world: https://asia.nikkei.com/location → 日经亚洲/世界
- nikkei-markets: https://asia.nikkei.com/business/markets → 日经亚洲/市场

Both pages share Nikkei's card template (StreamArticleCard +
SpotlightArticleCard + SecondaryArticleCard), so they reuse the
same recipe. Preview verified: validateArticle correctly skips
section pages, real articles have 1700-5000 chars body content.