fix: serve the website dist so Coolify answers GET /

Nixpacks built Vite but had no production start command, so Coolify returned Cannot GET /.

Co-authored-by: Cursor <cursoragent@cursor.com>

packages/website/Dockerfile

@@ -0,0 +1,12 @@
+# syntax=docker/dockerfile:1
+FROM node:22-alpine AS build
+WORKDIR /app
+COPY package.json package-lock.json ./
+RUN npm ci
+COPY . .
+RUN npm run build
+
+FROM nginx:1.27-alpine
+COPY nginx.conf /etc/nginx/conf.d/default.conf
+COPY --from=build /app/dist /usr/share/nginx/html
+EXPOSE 80