Add a FAQs section to the end of a ProstDev blog post for AEO. Use when the user wants to add or update frequently-asked questions / Q&A on a post (the "add FAQs", "FAQ section", "AEO Q&A" ask). Writes an optional `faqs` frontmatter array — answers GROUNDED in the post body, never fabricated — that renders a `## FAQs` section, mirrors into the `.md` endpoint, and emits FAQPage JSON-LD. Verifies with a build.
