fix(library): index native completions and refresh background downloads

lib/services/native_download_history.dart

@@ -0,0 +1,26 @@
+import 'package:spotiflac_android/utils/logger.dart';
+
+/// A completed file and a persisted Library entry are separate guarantees.
+/// In particular, `already_exists` does not mean history was ever saved.
+Future<void> reconcileNativeDownloadHistory({
+  required Map<String, dynamic> result,
+  required Future<void> Function(Map<String, dynamic>) adopt,
+  required Future<void> Function() reload,
+  required Future<void> Function() persistFallback,
+}) async {
+  final historyItem = result['history_item'];
+  if (historyItem is Map) {
+    try {
+      await adopt(Map<String, dynamic>.from(historyItem));
+      return;
+    } catch (error) {
+      AppLogger('DownloadHistory').w(
+        'Failed to adopt native history item, retrying from download result: $error',
+      );
+    }
+  } else if (result['history_written'] == true) {
+    await reload();
+    return;
+  }
+  await persistFallback();
+}