feat(ruby-client): 新增 Ruby 客户端 SDK 及 demo，移除 C 语言支持

- 新增 kenaito-conf-ruby-client（Ruby 2.5+）及对应 demo
- 新增 Dockerfile.ruby
- README 技术栈移除 C，项目结构补充 Ruby 客户端
- README_EN.md 同步更新
- README_DOCKERFILE.md 补充 Ruby 构建命令

kenaito-conf-ruby-client-demo/app.rb

@@ -0,0 +1,74 @@
+require_relative '../kenaito-conf-ruby-client/lib/kenaito_conf'
+
+def get_env_var(key, default)
+  value = ENV[key]
+  (value && !value.empty?) ? value : default
+end
+
+# 配置值（可被远程配置覆盖）
+config_values = {
+  'database.host' => get_env_var('DATABASE_HOST', '192.168.1.1'),
+  'database.port' => get_env_var('DATABASE_PORT', '8888'),
+  'database.name' => get_env_var('DATABASE_NAME', 'xxxx'),
+  'database.user' => get_env_var('DATABASE_USER', 'xxxx'),
+  'database.password' => get_env_var('DATABASE_PASSWORD', 'xxxxxxxx')
+}
+
+config = Kenaito::Conf::Config.new(
+  base_url: get_env_var('KENAITO_BASE_URL', 'http://localhost:8080'),
+  app_name: get_env_var('KENAITO_APP_NAME', 'kenaito-ruby-demo'),
+  env: get_env_var('KENAITO_ENV', 'daily'),
+  version: get_env_var('KENAITO_VERSION', 'latest'),
+  token: get_env_var('KENAITO_TOKEN', ''),
+  sync_interval: get_env_var('KENAITO_SYNC_INTERVAL', '10').to_i,
+  cache_dir: get_env_var('KENAITO_CACHE_DIR', '.')
+)
+
+client = Kenaito::Conf::Client.new(config)
+
+# 监听配置变更
+client.on_change do |changed|
+  puts "Config changed:"
+  changed.each do |key, value|
+    puts "  #{key} = #{value}"
+    if config_values.key?(key)
+      config_values[key] = value
+      puts "  [updated] #{key} = #{value}"
+    end
+  end
+end
+
+# 启动客户端
+begin
+  client.start
+  remote = client.get_all
+  config_values.each do |key, _|
+    if remote.key?(key)
+      config_values[key] = remote[key]
+    end
+  end
+  puts "loaded #{remote.size} configs from remote\n\n"
+rescue => e
+  puts "Failed to init config client, using local defaults: #{e.message}\n\n"
+end
+
+# 显示当前配置
+puts "Current configs:"
+config_values.keys.sort.each do |key|
+  puts "  #{key} = #{config_values[key]}"
+end
+
+puts "\nListening for config changes... (press Ctrl+C to stop)\n"
+
+# 信号处理
+trap('INT') do
+  puts "\nShutting down..."
+  client.stop_client
+  exit(0)
+end
+
+# 同步循环
+until client.stop
+  client.sync_once
+  sleep(config.sync_interval)
+end