feat: 新增 C++ 和 Rust 客户端 SDK 及 Docker 构建支持

- 新增 kenaito-conf-cpp-client / kenaito-conf-rust-client 及对应 demo
- 新增 Dockerfile.cpp / Dockerfile.rust
- README 目录结构补充 C++/Rust 客户端
- README_DOCKERFILE 补充 Windows docker run 命令，新增 C++/Rust 段落

kenaito-conf-cpp-client-demo/CMakeLists.txt

@@ -0,0 +1,12 @@
+cmake_minimum_required(VERSION 3.10)
+project(kenaito-conf-cpp-client-demo LANGUAGES CXX)
+
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+# 引入客户端库
+add_subdirectory(../kenaito-conf-cpp-client ${CMAKE_BINARY_DIR}/kenaito-conf-cpp-client)
+
+add_executable(demo main.cpp)
+
+target_link_libraries(demo PRIVATE kenaito_conf_client)

kenaito-conf-cpp-client-demo/main.cpp

@@ -0,0 +1,90 @@
+#include <kenaito_conf/client.h>
+#include <iostream>
+#include <cstdlib>
+#include <csignal>
+#include <thread>
+#include <chrono>
+#include <map>
+
+static kenaito::Client* g_client = nullptr;
+
+static void signal_handler(int) {
+    std::cout << "\nShutting down..." << std::endl;
+    if (g_client) g_client->stop();
+}
+
+static std::string get_env(const char* key, const std::string& default_val) {
+    const char* val = std::getenv(key);
+    return (val && val[0] != '\0') ? val : default_val;
+}
+
+static int get_env_int(const char* key, int default_val) {
+    const char* val = std::getenv(key);
+    if (val && val[0] != '\0') {
+        try { return std::stoi(val); } catch (...) {}
+    }
+    return default_val;
+}
+
+int main() {
+    std::map<std::string, std::string> config_values = {
+        {"database.host", "192.168.1.1"},
+        {"database.port", "8888"},
+        {"database.name", "xxxx"},
+        {"database.user", "xxxx"},
+        {"database.password", "xxxxxxxx"},
+    };
+
+    kenaito::Config config;
+    config.base_url = get_env("KENAITO_BASE_URL", "http://localhost:8080");
+    config.app_name = get_env("KENAITO_APP_NAME", "kenaito-springboot-demo");
+    config.env = get_env("KENAITO_ENV", "daily");
+    config.version = get_env("KENAITO_VERSION", "latest");
+    config.token = get_env("KENAITO_TOKEN", "");
+    config.sync_interval = get_env_int("KENAITO_SYNC_INTERVAL", 10);
+    config.cache_dir = get_env("KENAITO_CACHE_DIR", ".");
+
+    kenaito::Client client(config);
+    g_client = &client;
+
+    client.on_change([&config_values](const std::map<std::string, std::string>& changed) {
+        std::cout << "Config changed:" << std::endl;
+        for (const auto& kv : changed) {
+            std::cout << "  " << kv.first << " = " << kv.second << std::endl;
+            auto it = config_values.find(kv.first);
+            if (it != config_values.end()) {
+                it->second = kv.second;
+                std::cout << "  [updated] " << kv.first << " = " << kv.second << std::endl;
+            }
+        }
+    });
+
+    if (!client.start()) {
+        std::cerr << "Failed to init config client, using local defaults" << std::endl;
+    }
+
+    auto remote = client.get_all();
+    for (auto& kv : config_values) {
+        auto it = remote.find(kv.first);
+        if (it != remote.end()) {
+            kv.second = it->second;
+        }
+    }
+    std::cout << "loaded " << remote.size() << " configs from remote" << std::endl;
+
+    std::cout << "\nCurrent configs:" << std::endl;
+    for (const auto& kv : config_values) {
+        std::cout << "  " << kv.first << " = " << kv.second << std::endl;
+    }
+
+    std::cout << "\nListening for config changes... (press Ctrl+C to stop)" << std::endl;
+
+    std::signal(SIGINT, signal_handler);
+
+    while (true) {
+        client.sync_once();
+        std::this_thread::sleep_for(std::chrono::seconds(config.sync_interval));
+    }
+
+    return 0;
+}