enqueueForDownload method
Implementation
void enqueueForDownload(DownloadItem item) {
print('Enqueueing ${item.toJson()} for download');
if (locallyDownloadingIds.contains(item.id) || locallyQueuedIds.contains(item.id)) return;
locallyQueuedIds.add(item.id);
item.status = DownloadStatus.queued; // ✅ Set the status so _processQueue can find it!
downloads.refresh();
_managePollingTimer();
print('Starting _processQueue');
_processQueue();
}