The Dockerfile's `COPY package.json package-lock.json .npmrc ./` requires
the file to exist; the build was failing on a fresh clone with
`failed to compute cache key … "/.npmrc": not found`.
Contents are intentionally minimal: silence npm's audit/funding chatter
during CI/Docker builds and enable legacy-peer-deps so Astro 6 + Starlight
0.38 + @vite-pwa/astro can install together without npm's strict peer
resolver rejecting the lockfile.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
