Added components to article

lib/widget/operations/presentation/operation_view_enforcer.dart

@@ -4,8 +4,11 @@ import 'package:hl_lieferservice/widget/operations/bloc/operation_bloc.dart';
 
 import '../bloc/operation_state.dart';
 
-/// Listens to [OperationBloc] and shows SnackBars for success and error
-/// messages. Loading indicators are handled locally by each feature.
+/// Listens to [OperationBloc] and shows:
+/// - SnackBars for success and error messages.
+/// - A blocking modal barrier with a spinner while a mutation is in flight,
+///   so the user gets unambiguous "wait" feedback and cannot double-tap or
+///   navigate away mid-request.
 class OperationViewEnforcer extends StatelessWidget {
   final Widget child;
 
@@ -13,7 +16,7 @@ class OperationViewEnforcer extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return BlocListener<OperationBloc, OperationState>(
+    return BlocConsumer<OperationBloc, OperationState>(
       listener: (context, state) {
         if (state is OperationFinished && state.message != null) {
           ScaffoldMessenger.of(context).showSnackBar(
@@ -27,7 +30,44 @@ class OperationViewEnforcer extends StatelessWidget {
           );
         }
       },
-      child: child,
+      builder: (context, state) {
+        final isInProgress = state is OperationInProgress;
+        final progressMessage =
+            isInProgress ? state.message : null;
+
+        return Stack(
+          children: [
+            child,
+            if (isInProgress)
+              PopScope(
+                canPop: false,
+                child: Stack(
+                  children: [
+                    const ModalBarrier(
+                      dismissible: false,
+                      color: Colors.black54,
+                    ),
+                    Center(
+                      child: Column(
+                        mainAxisSize: MainAxisSize.min,
+                        children: [
+                          const CircularProgressIndicator(),
+                          if (progressMessage != null) ...[
+                            const SizedBox(height: 16),
+                            Text(
+                              progressMessage,
+                              style: const TextStyle(color: Colors.white),
+                            ),
+                          ],
+                        ],
+                      ),
+                    ),
+                  ],
+                ),
+              ),
+          ],
+        );
+      },
     );
   }
 }