fix: start nginx without resolving A-site at boot [deploy]

Dockerfile

@@ -1,12 +1,13 @@
 # CI 中先 pnpm build 产出 dist/；运行时由 nginx 托管，并把 /embed /images /api/contact 反代到 A 站
 FROM nginx:1.27-alpine
 
-# 集群内 A 站地址，可被 K8s env 覆盖
 ENV A_UPSTREAM=http://project57-deploy.ns-project57.svc.cluster.local:3000
-# 只替换 A_UPSTREAM，避免 envsubst 把 nginx 的 $host/$uri 等变量清空导致容器起不来
-ENV NGINX_ENVSUBST_FILTER=A_UPSTREAM
 
-COPY nginx.conf /etc/nginx/templates/default.conf.template
+# 不走 templates/envsubst，避免把 nginx 的 $host/$uri 清空
+COPY nginx.conf /etc/nginx/conf.d/default.conf
+COPY docker-entrypoint.d/40-a-upstream.sh /docker-entrypoint.d/40-a-upstream.sh
+RUN sed -i 's/\r$//' /docker-entrypoint.d/40-a-upstream.sh \
+  && chmod 0755 /docker-entrypoint.d/40-a-upstream.sh
 COPY dist /usr/share/nginx/html
 
 EXPOSE 3000