Mirrors msbls.de pattern, simplified (no mbrian-core submodule clone).
UID note: oven/bun:1-alpine has a built-in 'bun' user at UID/GID 1000 and
`addgroup -u 1000` on top of it breaks the build silently. mExDraw#14
(commit fc62b9c) lost ~4 weeks of Dokploy deploys to that. Comment in the
Dockerfile so the next person doesn't trip over the same.
Production build verified locally: vite build ✓ (4.08s).
