build(postgres): 更新生产环境PostgreSQL镜像版本至v18

调整数据卷挂载路径以适配PostgreSQL v18版本，并更新镜像标签变量为IMAGE_TAG_V18

dbSer/postgres/prod.stack.yml

@@ -4,7 +4,7 @@
 services:
 
   postgres:
-    image: ${IMAGE_TAG}
+    image: ${IMAGE_TAG_V18}
     container_name: prod-postgres
     restart: always
     shm_size: 256mb
@@ -14,7 +14,9 @@ services:
       - POSTGRES_INITDB_ARGS=--auth-host=${POSTGRES_HOST_AUTH_METHOD}
       - TZ=Asia/Shanghai
     volumes:
-      - /data/volumes/postgres/data:/var/lib/postgresql/data
+      # >=17 版本，数据目录为 /var/lib/postgresql
+      # <=16 版本，数据目录为 /var/lib/postgresql/data
+      - /data/volumes/postgres/data:/var/lib/postgresql
       - /etc/timezone:/etc/timezone:ro
       - /etc/localtime:/etc/localtime:ro
     ports: