Offer Claude sign-in from failed sessions

server/src/session/transcript.rs

@@ -873,6 +873,9 @@ mod tests {
                 tokens: 42,
                 context: Some(42),
             },
+            Event::AuthenticationRequired {
+                message: "sign in again".into(),
+            },
             Event::Error {
                 message: "boom".into(),
             },