bxcore, loopd: TurnDone says whether the session has read untrusted content

Co-Authored-By: ornith-1.5-35b-a3b <agent@wntrmute.dev>

crates/gatewayd/tests/support/fake_loop.rs

@@ -43,6 +43,7 @@ pub fn done(content: &str) -> Reply {
     let msg = Message::TurnDone(TurnDone {
         content: content.to_string(),
         usage: USAGE,
+        untrusted: false,
     });
     Reply::Frame(Envelope {
         v: PROTOCOL_VERSION,