add scanned barcode label widget

+import 'package:flutter/material.dart';
+import 'package:mobile_scanner/mobile_scanner.dart';
+
+class ScannedBarcodeLabel extends StatelessWidget {
+  const ScannedBarcodeLabel({
+    super.key,
+    required this.barcodes,
+  });
+
+  final Stream<BarcodeCapture> barcodes;
+
+  @override
+  Widget build(BuildContext context) {
+    return StreamBuilder(
+      stream: barcodes,
+      builder: (context, snaphot) {
+        final scannedBarcodes = snaphot.data?.barcodes ?? [];
+
+        if (scannedBarcodes.isEmpty) {
+          return const Text(
+            'Scan something!',
+            overflow: TextOverflow.fade,
+            style: TextStyle(color: Colors.white),
+          );
+        }
+
+        return Text(
+          scannedBarcodes.first.displayValue ?? 'No display value.',
+          overflow: TextOverflow.fade,
+          style: const TextStyle(color: Colors.white),
+        );
+      },
+    );
+  }
+}