test(ci): ignore test_engine_stops_on_flag in CI

The test requires a terminal (crossterm EventStream) which is unavailable
in CI environments, causing timeouts on Windows. This mirrors the existing
test_tick_increments_frame_count test which has the same ignore attribute.

Author: echobt

src/cortex-core/src/frame_engine.rs

@@ -665,6 +665,7 @@ mod tests {
     }
 
     #[tokio::test]
+    #[ignore = "Requires terminal (crossterm EventStream) which is unavailable in CI"]
     async fn test_engine_stops_on_flag() {
         let (tx, mut rx) = create_event_channel();
         let running = Arc::new(AtomicBool::new(true));