Added class clearance fixes and improvements

lib/utils/download_helper.dart

@@ -0,0 +1,29 @@
+import 'dart:typed_data';
+
+import 'package:file_selector/file_selector.dart';
+
+class SaveResult {
+  final String? path;
+  final bool canceled;
+
+  const SaveResult({this.path, required this.canceled});
+}
+
+Future<SaveResult> saveBytes(
+  Uint8List bytes,
+  String filename, {
+  String? mimeType,
+}) async {
+  final safeName = filename.trim().isEmpty ? 'export.bin' : filename.trim();
+  final location = await getSaveLocation(suggestedName: safeName);
+  if (location == null) {
+    return const SaveResult(canceled: true);
+  }
+  final file = XFile.fromData(
+    bytes,
+    mimeType: mimeType ?? 'application/octet-stream',
+    name: safeName,
+  );
+  await file.saveTo(location.path);
+  return SaveResult(path: location.path, canceled: false);
+}