Function enqueue_drop_files 

pub fn enqueue_drop_files(events: &Arc<Mutex<EventState>>, paths: &[PathBuf])

Push a freshly-dropped file batch onto the queue as a drop_files event.

Called from the UI layer when the GPUI canvas receives an external file drop. paths are encoded as a UTF-8 JSON array (e.g. ["/tmp/a.png","/tmp/b.png"]).