Build self-contained macOS client and verify native beta path

extension/src/platform/ScriptLib/PythonBoot.cpp

@@ -49,6 +49,7 @@
 
 #include <condition_variable>
 #include <cstdlib>
+#include <filesystem>
 #include <memory>
 #include <mutex>
 #include <pthread.h>
@@ -346,8 +347,18 @@ bool Start(const char* stdlib_path, std::string* error)
 		return true;
 
 	// 40250 Main (UserInterface.cpp:410): if (LocaleService_LoadGlobal(hInstance)) SetDefaultCodePage(...).
-	LocaleService_LoadConfig("locale.cfg");
+	std::string locale_config = "locale.cfg";
+	if (const char* client = std::getenv("MT_40250_CLIENT"))
+		locale_config = (std::filesystem::path(client) / "locale.cfg").string();
+	LocaleService_LoadConfig(locale_config.c_str());
 	SetDefaultCodePage(LocaleService_GetCodePage());
+	if (const char* data_dir = std::getenv("MT_40250_USER_DATA_DIR"))
+	{
+		std::error_code ec;
+		std::filesystem::current_path(data_dir, ec);
+		if (ec)
+			return fail(error, "cannot use player settings directory: " + ec.message());
+	}
 
 	const std::string stdlib = (stdlib_path && *stdlib_path) ? stdlib_path : PythonHost::DefaultStdLibPath();
 	if (stdlib.empty())