builder: retain Cargo config for run and correct acceptance checks

host/src/process/http.rs

@@ -49,7 +49,7 @@ impl WasiHttpHooks for Hooks {
                 if request.method() == http::Method::POST && request.uri().path() == "/cargo" {
                     return Ok((
                         crate::api::stream(&router, request),
-                        Box::new(async { Ok(()) }),
+                        Box::new(async { Ok(()) }) as Io,
                     ));
                 }
                 return Ok(response(crate::api::handle(&router, caller, request).await));