Clarify network and test execution contracts

src/session_tests.rs

@@ -1,5 +1,6 @@
-//! Real FTP commands over a native test socket, with an async local server.
-//! This verifies guest recovery; WASM host integration is exercised separately.
+//! Real FTP commands against an async local server. The generated guest API is
+//! synchronous, so each guest call is isolated with `spawn_blocking`; production
+//! WASM host integration is exercised separately.
 
 use super::Ftp;
 use memona_plugin_sdk::{ErrorCode, Guest, Locator, Setting};

src/test_host.rs

@@ -1,5 +1,6 @@
-//! Native test transport. Guest calls run only inside `spawn_blocking`;
-//! production WASM always uses the host's sockets and network policy.
+//! Native test transport for the generated synchronous `Guest` API. It cannot
+//! await a Tokio socket, so tests confine it to `spawn_blocking` while their FTP
+//! server remains async. Production WASM always uses the host's async sockets.
 
 use std::cell::RefCell;
 use std::io::{Read, Write};