Reduce Docker build memory usage

Dockerfile

@@ -8,6 +8,7 @@ RUN npm run build
 
 FROM debian:bookworm-slim
 ARG SINGBOX_VERSION=1.12.13
+COPY --from=ui-build /app/dist /app/dist
 
 RUN apt-get update \
     && apt-get install -y --no-install-recommends ca-certificates curl iptables iproute2 nodejs dumb-init \
@@ -27,7 +28,6 @@ RUN set -eux; \
     rm -rf /tmp/sing-box*
 
 WORKDIR /app
-COPY --from=ui-build /app/dist /app/dist
 COPY package.json /app/package.json
 COPY src/server /app/src/server
 COPY entrypoint.sh /entrypoint.sh