chore: 删除多个客户端模块

移除以下未完成的客户端模块：
- C++ 客户端和 demo
- .NET 客户端和 demo
- Kotlin 客户端和 demo
- Lua 客户端和 demo
- PHP 客户端和 demo
- Ruby 客户端和 demo
- Rust 客户端和 demo

更新根目录 README.md，移除相关说明。

kenaito-conf-ruby-client/lib/kenaito_conf.rb

@@ -1,165 +0,0 @@
-# frozen_string_literal: true
-
-require 'net/http'
-require 'json'
-
-module KenaitoConf
-  class Config
-    attr_accessor :base_url, :app_name, :env, :version, :token, :sync_interval, :ignore_global, :cache_dir
-
-    def initialize(options = {})
-      @base_url = options[:base_url] || ''
-      @app_name = options[:app_name] || ''
-      @env = options[:env] || 'dev'
-      @version = options[:version] || 'latest'
-      @token = options[:token] || ''
-      @sync_interval = options[:sync_interval] || 60
-      @ignore_global = options[:ignore_global] || false
-      @cache_dir = options[:cache_dir] || '.'
-    end
-  end
-
-  class Cache
-    CACHE_FILE = 'config-cache.json'
-
-    def initialize(cache_dir = '.')
-      @cache_dir = cache_dir
-    end
-
-    def write(data)
-      File.write(File.join(@cache_dir, CACHE_FILE), JSON.pretty_generate(data))
-    end
-
-    def read
-      path = File.join(@cache_dir, CACHE_FILE)
-      return nil unless File.exist?(path)
-      JSON.parse(File.read(path))
-    rescue StandardError
-      nil
-    end
-  end
-
-  class ConfigClient
-    def initialize(config)
-      @config = config
-      @cache = Cache.new(config.cache_dir)
-      @configs = {}
-      @last_time = 0
-      @handlers = []
-      @started = false
-    end
-
-    def on_change(&handler)
-      @handlers << handler
-    end
-
-    def get(key)
-      @configs[key]
-    end
-
-    def get_all
-      @configs.dup
-    end
-
-    def start
-      return if @started
-      @started = true
-
-      begin
-        fetch_all
-      rescue StandardError => e
-        warn "[ConfigClient] fetch all configs error: #{e.message}, trying cache"
-        cached = @cache.read
-        if cached
-          apply_configs(cached)
-          warn "[ConfigClient] loaded #{@configs.size} configs from cache"
-        else
-          raise "fetch configs failed and no cache: #{e.message}"
-        end
-      end
-
-      Thread.new do
-        loop do
-          sleep @config.sync_interval
-          begin
-            fetch_changed
-          rescue StandardError => e
-            warn "[ConfigClient] sync error: #{e.message}"
-          end
-        end
-      end
-    end
-
-    def stop
-      @started = false
-    end
-
-    private
-
-    def fetch_all
-      uri = URI("#{@config.base_url}/api/fetchAllConfigs")
-      http = Net::HTTP.new(uri.host, uri.port)
-      http.read_timeout = 10
-
-      request = Net::HTTP::Post.new(uri.path, 'Content-Type' => 'application/json')
-      request.body = JSON.generate({
-        appName: @config.app_name,
-        env: @config.env,
-        version: @config.version,
-        ignoreGlobal: @config.ignore_global,
-        token: @config.token
-      })
-
-      response = http.request(request)
-      raise "HTTP #{response.code}" unless response.code == '200'
-
-      data = JSON.parse(response.body)
-      raise "server error: #{data['msg']}" if data['code'] && data['code'] != 0
-
-      @last_time = data['latest.fetch.timestamp'].to_i if data['latest.fetch.timestamp']
-
-      @cache.write(data)
-      apply_configs(data)
-      warn "[ConfigClient] fetched #{@configs.size} configs"
-    end
-
-    def fetch_changed
-      uri = URI("#{@config.base_url}/api/fetchChangedConfigs")
-      http = Net::HTTP.new(uri.host, uri.port)
-      http.read_timeout = 10
-
-      request = Net::HTTP::Post.new(uri.path, 'Content-Type' => 'application/json')
-      request.body = JSON.generate({
-        appName: @config.app_name,
-        env: @config.env,
-        version: @config.version,
-        lastTime: @last_time,
-        ignoreGlobal: @config.ignore_global,
-        token: @config.token
-      })
-
-      response = http.request(request)
-      result = JSON.parse(response.body)
-      raise "server error" if !result['code'] || result['code'] != 0
-
-      changed_data = result['data'] || {}
-      @last_time = changed_data.delete('latest.fetch.timestamp').to_i if changed_data['latest.fetch.timestamp']
-
-      changed = {}
-      changed_data.each do |k, v|
-        changed[k] = v
-      end
-
-      @configs.merge!(changed)
-      @handlers.each { |h| h.call(changed) rescue warn "[ConfigClient] handler error: #{$!.message}" }
-    end
-
-    def apply_configs(data)
-      data.each do |k, v|
-        next if k.start_with?('kenaito.') || k == 'latest.fetch.timestamp'
-        next unless v.is_a?(String)
-        @configs[k] = v
-      end
-    end
-  end
-end