Run wavelength-demo locally

Run the scroll-driven promo page from a fresh clone of Geoffe-Ga/wavelength-demo. Verified against the repo state of 2026-07-31.

Prerequisites

• Node.js and npm

Steps

1. Install from the lockfile:

npm ci

1. Start the Vite dev server:

npm run dev

1. For a production build and preview:

npm run build     # tsc -b && vite build
npm run preview

Verify

• The dev server URL renders the page: a sine wave fixed mid-screen, header bars sweeping past on scroll, phase copy fading onto the wave.
• Quality gates pass: ./scripts/check-all.sh exits 0 (tests, lint, typecheck; the repo holds itself to 90% coverage and a mutation-score gate per its CLAUDE.md).