refactor: cleanup unused imports and add const optimizations

app/lib/main.dart

@@ -303,7 +303,7 @@ class MockTourRepository implements TourRepository {
     return Right(CounterOverview(
       tourId: tourId,
       pageId: pageId,
-      groups: [],
+      groups: const [],
     ));
   }
   

app/lib/presentation/blocs/scan/scan_bloc.dart

@@ -151,7 +151,7 @@ class ScanBloc extends Bloc<ScanEvent, ScanState> {
         tour: currentTour,
       ));
     } else {
-      emit(ScanError(
+      emit(const ScanError(
         message: 'Fehler: Ungültiger Barcode für Lager Beladung',
       ));
     }
@@ -835,7 +835,6 @@ class ScanBloc extends Bloc<ScanEvent, ScanState> {
     final result = await repository.createObject(
       type: event.type,
       code: event.barcode,
-      isManual: true,
     );
 
     result.fold(

app/lib/presentation/pages/tour_types/stock_start_page.dart

@@ -1,10 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import '../../../domain/entities/tour.dart';
-import '../../../domain/entities/counter.dart';
-import '../../../core/constants/app_constants.dart';
 import '../../blocs/scan/scan_bloc.dart';
-import '../../widgets/counter_grid.dart';
 import '../../widgets/recent_scans_list.dart';
 import '../scan/scan_page.dart';