three-layer public model shipped. Worlds/campaigns/articles with private: false are accessible without auth. Pundit policies updated to handle nil user; show actions in Worlds/Campaigns/Articles controllers skip auth and use marketing layout for guests. Explore page filters to is_public scope and cards link to world show pages. Sitemap controller at /sitemap.xml enumerates public worlds, campaigns, articles plus static marketing pages. robots.txt updated to allow /worlds/, /campaigns/, /articles/. og: and JSON-LD meta tags added to application layout; world/campaign/article show views provide meta_title, meta_description, og_image. MCP parity already complete (private field already on all tools). 382 tests green.
BL-009
Shipped