new plus button

test/backup_format_test.dart

@@ -4,7 +4,7 @@ import 'package:receipity/services/backup_format.dart';
 void main() {
   test('round-trips a backup document', () {
     const original = BackupDocument(
-      version: 2,
+      version: 3,
       exportedAt: '2026-08-29T12:00:00.000',
       darkMode: true,
       supermarkets: [
@@ -29,6 +29,7 @@ void main() {
         {
           'id': 8,
           'supermarket': 'Jumbo',
+          'name': 'Weekly shop',
           'shopped_at': '2026-08-29T12:00:00.000',
           'receipt_image_path': 'receipts/shop_8.jpg',
           'total': 1.5,
@@ -46,6 +47,9 @@ void main() {
           'unit_price': 1.5,
         },
       ],
+      shopTags: [
+        {'id': 1, 'shop_id': 8, 'tag': 'weekly', 'normalized_tag': 'weekly'},
+      ],
       shoppingLists: [
         {
           'id': 1,
@@ -71,7 +75,9 @@ void main() {
     expect(parsed.darkMode, isTrue);
     expect(parsed.products.single['name'], 'Milk');
     expect(parsed.shops.single['id'], 8);
+    expect(parsed.shops.single['name'], 'Weekly shop');
     expect(parsed.shopItems.single['product_id'], 1);
+    expect(parsed.shopTags.single['tag'], 'weekly');
     expect(parsed.shoppingLists.single['name'], 'Weekly');
     expect(parsed.shoppingListItems.single['name'], 'Milk');
     expect(parsed.images['products/product_1.jpg'], 'abc123');
@@ -95,6 +101,7 @@ void main() {
     expect(parsed.version, 1);
     expect(parsed.shoppingLists, isEmpty);
     expect(parsed.shoppingListItems, isEmpty);
+    expect(parsed.shopTags, isEmpty);
   });
 
   test('rejects a file that is not a Receipity backup', () {