feat: 添加多语言客户端 Docker 支持

- 新增 .NET 客户端 SDK 和 demo 项目
- 添加 Go/Node.js/Python/.NET/SpringBoot2 的 Dockerfile
- Go demo 支持从环境变量读取配置
- 创建 README_DOCKERFILE.md 文档说明 Docker 使用方法
- 更新根目录 README.md 标记 .NET 客户端为已支持

kenaito-conf-dotnet-client-demo/KenaitoConfDemo.csproj

@@ -0,0 +1,14 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="../kenaito-conf-dotnet-client/KenaitoConfClient.csproj" />
+  </ItemGroup>
+
+</Project>

kenaito-conf-dotnet-client-demo/Program.cs

@@ -0,0 +1,52 @@
+using Kenaito.Conf.Client;
+
+var config = new Config
+{
+    BaseUrl = "http://localhost:8080",
+    AppName = "kenaito-springboot-demo",
+    Env = "daily",
+    Version = "latest",
+    SyncInterval = 10,
+    CacheDir = "."
+};
+
+var client = new Client(config);
+
+client.OnChange(changed =>
+{
+    Console.WriteLine("Config changed:");
+    foreach (var kv in changed)
+    {
+        Console.WriteLine($"  {kv.Key} = {kv.Value}");
+    }
+});
+
+await client.StartAsync();
+
+Console.WriteLine("Current configs:");
+foreach (var kv in client.GetAll())
+{
+    Console.WriteLine($"  {kv.Key} = {kv.Value}");
+}
+
+var dbHost = client.Get("database.host");
+Console.WriteLine($"\ndatabase.host = {dbHost}");
+
+Console.WriteLine("\nListening for config changes... (press Ctrl+C to stop)");
+var cts = new CancellationTokenSource();
+Console.CancelKeyPress += (s, e) =>
+{
+    e.Cancel = true;
+    cts.Cancel();
+};
+
+try
+{
+    await Task.Delay(Timeout.Infinite, cts.Token);
+}
+catch (TaskCanceledException)
+{
+}
+
+Console.WriteLine("\nShutting down...");
+client.Stop();

kenaito-conf-dotnet-client-demo/README.md

@@ -0,0 +1,41 @@
+# Kenaito Config Center .NET Demo
+
+演示如何使用 kenaito-conf-dotnet-client 客户端库。
+
+## 本地运行
+
+```bash
+cd kenaito-conf-dotnet-client-demo
+dotnet run
+```
+
+## Docker 运行
+
+```bash
+# 在项目根目录执行
+docker build -f Dockerfile.dotnet -t kenaito-conf-dotnet-demo .
+
+docker run -it --rm \
+  -e CONFIG_CENTER_BASE_URL=http://host.docker.internal:8080 \
+  kenaito-conf-dotnet-demo
+```
+
+## 配置项
+
+修改 `Program.cs` 中的配置：
+
+```csharp
+var config = new Config
+{
+    BaseUrl = "http://localhost:8080",  // 配置中心地址
+    AppName = "kenaito-dotnet-demo",     // 应用名称
+    Env = "daily",                       // 环境
+    SyncInterval = 10                    // 同步间隔（秒）
+};
+```
+
+## 功能演示
+
+- 启动时拉取全量配置并打印
+- 监听配置变更，实时输出变更内容
+- 按 Ctrl+C 优雅退出