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)