- Add sitemap.ts and robots.ts
- pageMetadata() helper: consistent title, canonical URL, Open Graph,
Twitter card and feed alternate on every page
- Generated OG images: a site card, and per post either the cover image
or a branded title card (pre-rendered at build)
- BlogPosting JSON-LD on post pages
- Fail fast with a clear error when SITE_URL is missing
Content loading:
- Validate post frontmatter at build time and normalize dates to ISO
(fixes invalid <time datetime> values)
- Add draft: true support (drafts only render in development)
- Cache markdown rendering so metadata and page share one render
- Replace the three copy-pasted about/projects/setup pages with a shared
MarkdownPage component
