chore(import): improve error handling and add flyer integration

- Replace BadRequestException with UnauthorizedException for authentication failures in flyer-import and flyer-selection controllers
- Add bulk selection endpoint in FlyerSelectionController for creating multiple selections in one request
- Update FlyerSelectionModule to include new FlyerSelectionMatcherService and FlyerSelectionSyncController
- Extend FlyerSelectionService with createMany method for bulk operations
- Add new DTOs for bulk selection and receipt matching functionality
- Update ReceiptImportService to accept FlyerSelectionService dependency and track successful rows
- Extend SaveReceiptResponse with flyerAutoSync field for receipt-to-flyer matching results
- Add new API paths for flyer import and selection endpoints
- Update Flutter UI to include Flyer import tab and adjust tab controller length
- Add new domain models and repository methods for flyer import functionality
- Update test files to include new FlyerSelectionService dependency
- Modify .kilo plan documentation to reflect current system architecture

flutter/lib/features/import/presentation/import_screen.dart

@@ -1,9 +1,10 @@
 import 'package:flutter/material.dart';
 
-import 'recipe_import_tab.dart';
-import 'receipt_import_tab.dart';
+import 'flyer_import_tab.dart';
+import 'recipe_import_tab.dart';
+import 'receipt_import_tab.dart';
 
-/// Main import screen with tabs: Recept | Kvitto.
+/// Main import screen with tabs: Recept | Kvitto | Flyer.
 ///
 /// Fas 6a: Recept-fliken är implementerad.
 /// Fas 6b: Kvitto-fliken läggs till i ett senare steg.
@@ -18,10 +19,11 @@ class _ImportScreenState extends State<ImportScreen> {
   @override
   Widget build(BuildContext context) {
     return const TabBarView(
-      children: [
-        RecipeImportTab(),
-        ReceiptImportTab(),
-      ],
-    );
-  }
-}
+      children: [
+        RecipeImportTab(),
+        ReceiptImportTab(),
+        FlyerImportTab(),
+      ],
+    );
+  }
+}