feat: make server own products

lib/views/bar/bar_screen_view.dart

@@ -90,6 +90,23 @@ class _BarScreenViewState extends State<BarScreenView> {
     }
   }
 
+  void _showSyncProblem({required String title, required String description}) {
+    final l10n = AppLocalizations.of(context);
+    showDialog<void>(
+      context: context,
+      builder: (dialogContext) => AlertDialog(
+        title: Text(title),
+        content: SelectableText(description),
+        actions: [
+          TextButton(
+            onPressed: () => Navigator.of(dialogContext).pop(),
+            child: Text(l10n.close),
+          ),
+        ],
+      ),
+    );
+  }
+
   void _logout() {
     context.read<PinLockViewModel>().lock();
     context.read<AdminPinViewModel>().lock();
@@ -142,6 +159,32 @@ class _BarScreenViewState extends State<BarScreenView> {
               icon: const Icon(Icons.cloud_off_rounded),
             ),
           ],
+          // A failing sync is otherwise invisible: the bar keeps working
+          // offline while nothing from the website arrives
+          if (context.watch<RemoteSyncViewModel>().lastError
+              case final error?) ...[
+            const SizedBox(width: 6),
+            // Offline is normal for a bar; anything else needs attention
+            if (context.watch<RemoteSyncViewModel>().isOffline)
+              IconButton(
+                tooltip: l10n.offline,
+                onPressed: () => _showSyncProblem(
+                  title: l10n.offline,
+                  description: l10n.offlineDescription,
+                ),
+                icon: const Icon(Icons.wifi_off_rounded),
+              )
+            else
+              IconButton(
+                tooltip: '${l10n.syncProblem}: $error',
+                color: Theme.of(context).colorScheme.error,
+                onPressed: () => _showSyncProblem(
+                  title: l10n.syncProblem,
+                  description: '${l10n.syncProblemDescription}\n\n$error',
+                ),
+                icon: const Icon(Icons.sync_problem_rounded),
+              ),
+          ],
           const SizedBox(width: 6),
           IconButton(
             tooltip: l10n.refresh,