brand/ ships every reusable mark plus a browseable kit page:
* logo.svg — full colour wordmark (star + sirius.x, .x in acid green)
* logo-mono.svg — currentColor version for print / one-colour merch
* favicon.svg — 64×64 rounded square, scales cleanly to 16×16
* avatar.svg — 512×512 square, hard corners (platforms round-mask)
* banner.svg — 1200×630 OG / Twitter Card canvas, crop-tolerant layout
* index.html — brand-kit page: asset previews + download links, full
colour palette with names/hex, typography sample, do/don't guidance,
MIT-attribution notice.
Nav: added 🎨 Brand link to every sirius.x page (landing, portal, docs,
theseus). og:image on every page updated to point at /brand/banner.svg
instead of the wordmark logo — social crawlers get a proper 1200×630
banner with title, tagline, and mark instead of a thin logo strip.
Kept /assets/favicon.svg and /assets/logo.svg in place so existing
external references (Nostr metadata, third-party embeds) don't break.
