fix(download): recover queue after worker timeout (#524)

lib/providers/download_queue_provider.dart

@@ -75,6 +75,17 @@ bool canStartForegroundDownloadForLifecycle(AppLifecycleState? lifecycleState) {
   return lifecycleState == AppLifecycleState.resumed;
 }
 
+String nativeWorkerStatusAfterSnapshotStop({
+  required bool workerRunning,
+  required String status,
+}) {
+  if (workerRunning) return status;
+  return switch (status) {
+    'preparing' || 'downloading' || 'finalizing' => 'queued',
+    _ => status,
+  };
+}
+
 /// Keeps a download in its finalizing state until its durable Library record
 /// has been written. If persistence fails, completion is deliberately not
 /// published so the queue can surface the error instead of losing the file

lib/providers/download_queue_provider_native_worker.dart

@@ -863,6 +863,7 @@ extension _DownloadQueueNativeWorker on DownloadQueueNotifier {
     if (itemSnapshots.isEmpty) {
       return;
     }
+    final workerRunning = snapshot['is_running'] == true;
 
     for (final itemSnapshot in itemSnapshots) {
       final itemId = itemSnapshot['item_id']?.toString() ?? '';
@@ -872,7 +873,10 @@ extension _DownloadQueueNativeWorker on DownloadQueueNotifier {
       final context = contexts[itemId];
       if (context == null) continue;
 
-      final status = itemSnapshot['status']?.toString() ?? 'queued';
+      final status = nativeWorkerStatusAfterSnapshotStop(
+        workerRunning: workerRunning,
+        status: itemSnapshot['status']?.toString() ?? 'queued',
+      );
       final progress = ((itemSnapshot['progress'] as num?)?.toDouble() ?? 0.0)
           .clamp(0.0, 1.0)
           .toDouble();