add ssr

Dockerfile

@@ -1,4 +1,4 @@
-# Build: generates /dist (Astro static site + Sanity Studio SPA)
+# Build: generates /dist (Astro SSR build + Sanity Studio SPA)
 FROM node:22-alpine AS builder
 WORKDIR /app
 COPY package*.json ./
@@ -6,9 +6,11 @@ RUN npm ci
 COPY . .
 RUN npm run build
 
-# Frontend: Nginx serving the static site + Sanity Studio SPA
-FROM nginx:alpine AS frontend
-RUN rm /etc/nginx/conf.d/default.conf
-COPY nginx.conf /etc/nginx/conf.d/default.conf
-COPY --from=builder /app/dist /usr/share/nginx/html
+# Server: Node.js running the Astro SSR server
+FROM node:22-alpine
+WORKDIR /app
+COPY --from=builder /app/node_modules ./node_modules
+COPY --from=builder /app/dist ./dist
+ENV PORT=80
 EXPOSE 80
+CMD ["node", "./dist/server/entry.mjs"]