checkpointEditedRecently method
Implementation
bool checkpointEditedRecently(String checkpointKey, {DateTime? now}) {
final editedAt = _editedCheckpointAtByKey[checkpointKey];
if (editedAt == null) return false;
final cutoff = (now ?? DateTime.now()).subtract(recentWindow);
return !editedAt.isBefore(cutoff);
}