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/core/api/api_paths.dart

@@ -33,10 +33,20 @@ class CategoryApiPaths {
   static const tree = '/categories/tree';
 }
 
-class ReceiptImportApiPaths {
-  static const refreshCategories = '/receipt-import/refresh-categories';
-  static const unitMappings = '/receipt-import/unit-mappings';
-}
+class ReceiptImportApiPaths {
+  static const refreshCategories = '/receipt-import/refresh-categories';
+  static const unitMappings = '/receipt-import/unit-mappings';
+}
+
+class FlyerImportApiPaths {
+  static const parse = '/flyer-import/parse';
+}
+
+class FlyerSelectionApiPaths {
+  static String bySession(int sessionId) => '/flyer-sessions/$sessionId/selections';
+  static String bulkBySession(int sessionId) => '/flyer-sessions/$sessionId/selections/bulk';
+  static const open = '/flyer-selections/open';
+}
 
 class HelpTextApiPaths {
   static String byKey(String key) => '/help-texts/${Uri.encodeComponent(key)}';
@@ -131,4 +141,4 @@ class MealPlanApiPaths {
 
   static String removeByDate(String date) =>
     '$list/${Uri.encodeComponent(date)}';
-}
+}