A minimal HTTP client and fluent controller for the Toxiproxy control API (create/enable/disable proxies, add/remove toxics), plus glue that turns proxy controls into core XaAction callbacks. Main code depends only on the JDK (java.net.http) and xa-tester-core; tests fake the Toxiproxy REST API with the JDK's built-in HttpServer instead of a real Toxiproxy process or container.