docs(config_center/zookeeper): align README and comments with actual code (#1094)

The sample's README and an inline comment had three inconsistencies that
confused users following the docs:

- Triple port: README showed `port: 20000`, but the YAML pushed to ZK in
  go-server/cmd/main.go uses `port: 50000`. The server actually listens
  on 50000, so update README to match.

- DataID: README and the inline comment in main.go used
  `dubbo-go-samples-configcenter-zookeeper-server`, but the actual
  WithDataID() call and the ZK path use
  `dubbo-go-samples-configcenter-zookeeper-go-server` (with `-go-`).
  Update both docs to match the code.

- Zookeeper start command: README said `docker compose up -d zookeeper`,
  but the repo has no compose file for it, so the command fails.
  Replace with a concrete `docker run` and a link to the official
  Zookeeper installation guide.

Both README.md and README_zh.md are kept in sync.

Closes #1081
Closes #1082
Closes #1084

Author: Harry33t

config_center/zookeeper/README.md

@@ -5,11 +5,17 @@
 This example shows dubbo-go's dynamic configuration feature with Zookeeper as config-center.
 
 ## 2. How to run
-### Run the following commands under `repo root`:
+
+### Start a Zookeeper instance
+
+Make sure a Zookeeper instance is listening on `127.0.0.1:2181`. The simplest way is to start one with Docker:
 
 ```
-docker compose up -d zookeeper
+docker run -d --name zookeeper -p 2181:2181 zookeeper:3.8
 ```
+
+Or follow the [Zookeeper installation guide](https://zookeeper.apache.org/doc/current/zookeeperStarted.html) to install it locally.
+
 ### Configure the configuration file into zookeeper
 
 ```yaml
@@ -22,7 +28,7 @@ dubbo:
   protocols:
     triple:
       name: tri
-      port: 20000
+      port: 50000
   provider:
     services:
       GreeterProvider:
@@ -36,7 +42,7 @@ If there is no preexisting configuration, that is fine as well, because the samp
 
 ```go
 zkOption := config_center.WithZookeeper()
-dataIdOption := config_center.WithDataID("dubbo-go-samples-configcenter-zookeeper-server")
+dataIdOption := config_center.WithDataID("dubbo-go-samples-configcenter-zookeeper-go-server")
 addressOption := config_center.WithAddress("127.0.0.1:2181")
 groupOption := config_center.WithGroup("dubbogo")
 ins, err := dubbo.NewInstance(

config_center/zookeeper/README_zh.md

@@ -5,10 +5,17 @@
 本示例演示Dubbo-Go以ZooKeeper为配置中心来实现动态配置功能
 
 ## 2. 如何运行
-### 在 `仓库根目录` 目录下执行：
+
+### 启动 Zookeeper 实例
+
+确保有一个 Zookeeper 实例监听在 `127.0.0.1:2181`。最简单的方式是用 Docker 启动一个：
+
 ```
-docker compose up -d zookeeper
+docker run -d --name zookeeper -p 2181:2181 zookeeper:3.8
 ```
+
+或者参考 [Zookeeper 安装文档](https://zookeeper.apache.org/doc/current/zookeeperStarted.html) 在本地安装。
+
 ### 把配置文件配置到zookeeper中
 
 ```yaml
@@ -21,7 +28,7 @@ dubbo:
   protocols:
     triple:
       name: tri
-      port: 20000
+      port: 50000
   provider:
     services:
       GreeterProvider:
@@ -35,7 +42,7 @@ dubbo:
 
 ```go
 zkOption := config_center.WithZookeeper()
-dataIdOption := config_center.WithDataID("dubbo-go-samples-configcenter-zookeeper-server")
+dataIdOption := config_center.WithDataID("dubbo-go-samples-configcenter-zookeeper-go-server")
 addressOption := config_center.WithAddress("127.0.0.1:2181")
 groupOption := config_center.WithGroup("dubbogo")
 ins, err := dubbo.NewInstance(

config_center/zookeeper/go-server/cmd/main.go

@@ -87,7 +87,7 @@ func main() {
 	}
 }
 
-const configCenterZKServerConfig = `## set in config center, group is 'dubbogo', dataid is 'dubbo-go-samples-configcenter-zookeeper-server', namespace is default
+const configCenterZKServerConfig = `## set in config center, group is 'dubbogo', dataid is 'dubbo-go-samples-configcenter-zookeeper-go-server', namespace is default
 dubbo:
   registries:
     demoZK: