Landing kit from go-fileshare: neutral backgrounds, brand from the logo, fileshare's skeleton

[tannevaled]

Brings the landing in line with go-fileshare.github.io, keeping go-ndarray's logo and emerald accent.

• Stylesheet: go-fileshare's, byte for byte, from the brand workshop's kit (logos/landing-kit).
• Brand: [params.brand] is derived from the logo's gradient.
  • base is #047857, 5.48:1 on white (AA, where the old #059669 was 3.77:1).
  • bright is #34d399.
• Backgrounds: the surfaces tables that tinted the background emerald are gone. It now matches go-fileshare pixel for pixel: #ffffff light, #0b0e14 dark.
• Skeleton:
  • the GitHub mark on the buttons, via the kit's partial;
  • nav Why / Example / API / Repositories, with the documentation as the primary button;
  • a full-width terminal with the verbatim output of the hero's example, run against github.com/go-ndarray/ndarray@v0.7.0;
  • #api cards from [[params.families]]. Every function named there was checked to exist in v0.7.0 (go doc, with a negative control).
• SIMD lists: riscv64 added (RVV since v0.7.0, per the README).
• CI: ci.yml (the site builds and names ndarray, docs and brand) and links.yml (every link of the built site resolves).

Verified locally with the kit:

• text and pixel checks against go-fileshare pass, in light and dark;
• 3/3 repositories named on the page;
• 9/9 links resolve;
• built with pkgx hugo@0.167.0.

The landing was handed over by the session that owns go-ndarray's v0.7.0 surfaces (its #19 is merged).

🤖 Generated with Claude Code