fix: web API 502 — use Podman-local DNS for gateway proxy

Mount nginx template with NGINX_LOCAL_RESOLVERS and require web→gateway health in deploy checks.

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

docker-compose.yml

@@ -121,9 +121,11 @@ services:
     volumes:
       # :Z 供 Podman/SELinux 可读；纯 Docker 也兼容
       - ./web/dist:/usr/share/nginx/html:ro,Z
-      - ./web/nginx.conf:/etc/nginx/conf.d/default.conf:ro,Z
+      # 走官方 templates + envsubst，注入容器 /etc/resolv.conf 里的 DNS
+      - ./web/nginx.conf.template:/etc/nginx/templates/default.conf.template:ro,Z
     environment:
       TZ: Asia/Shanghai
+      NGINX_ENTRYPOINT_LOCAL_RESOLVERS: "1"
     networks:
       default:
         aliases: