Per-release OG cards — GET /og/blog/v<X.Y.Z>.png composes a 1200×630 card for each minor+ release: dark radial background, hero avatar (deterministic from navii <version> seed + mood: happy, transparent so the mascot floats on the gradient), version pill, headline parsed from CHANGELOG, date, and navii.dev/blog brand mark. Cached per version. /blog/v<X.Y.Z> now sets og:image + twitter:image to this URL so social previews show the release-specific card instead of the generic landing OG image.