modify: rust worker

workers/rsdemo/echo.toml

@@ -0,0 +1,11 @@
+# rsdemo.echo —— POST 端点，演示 user_info 信封透传
+[POST]
+summary = "Rust 参考插件：回声（透传网关认证用户信息）"
+params = ["msg: str"]
+auth_required = true
+
+[POST.response_model]
+echo = { type = "str", required = true }
+user_info = { type = "any", required = false }
+worker_id = { type = "str", required = false, default = "" }
+timestamp = { type = "float", required = true }