fix appointment cancellation

backend/src/main/java/com/petshop/backend/service/AppointmentService.java

@@ -196,8 +196,9 @@ public class AppointmentService {
             throw new ResourceNotFoundException("Appointment not found");
         }
 
-        if (!"Booked".equalsIgnoreCase(appointment.getAppointmentStatus())) {
-            throw new IllegalArgumentException("Only booked appointments can be cancelled");
+        String status = appointment.getAppointmentStatus();
+        if (!"Booked".equalsIgnoreCase(status) && !"Scheduled".equalsIgnoreCase(status)) {
+            throw new IllegalArgumentException("Only booked or scheduled appointments can be cancelled");
         }
 
         appointment.setAppointmentStatus("Cancelled");