🐛 fix breaking changes with carbon 3

Laravel 11 supports both Carbon 2 and Carbon 3. Carbon is a date manipulation library utilized extensively by Laravel and packages throughout the ecosystem. If you upgrade to Carbon 3, be aware that diffIn* methods now return floating-point numbers and may return negative values to indicate time direction, which is a significant change from Carbon 2. Review Carbon's change log and documentation for detailed information on how to handle these and other changes.

app/Http/Controllers/Backend/Transport/TrainCheckinController.php

@@ -309,7 +309,7 @@ public static function refreshDistanceAndPoints(Status $status, bool $resetPolyl
     public static function calculateCheckinDuration(Checkin $checkin, bool $update = true): int {
         $departure = $checkin->manual_departure ?? $checkin->originStopover->departure ?? $checkin->departure;
         $arrival   = $checkin->manual_arrival ?? $checkin->destinationStopover->arrival ?? $checkin->arrival;
-        $duration  = $arrival->diffInMinutes($departure);
+        $duration  = $departure->diffInMinutes($arrival);
         //don't use eloquent here, because it would trigger the observer (and this function) again
         if ($update) {
             DB::table('train_checkins')->where('id', $checkin->id)->update(['duration' => $duration]);