fix(web): use red (error color) for unread badge instead of green

apps/app_seeds/lib/ui/unread_badge.dart

@@ -4,7 +4,6 @@ import 'package:flutter/material.dart';
 
 import '../di/injector.dart';
 import '../services/unread_service.dart';
-import 'theme.dart';
 
 /// Wraps [child] with a small live unread-count badge. It listens to the
 /// app-wide [UnreadService] and rebuilds whenever a count changes: on a new
@@ -79,7 +78,7 @@ class _UnreadBadgeState extends State<UnreadBadge> {
     return Badge(
       isLabelVisible: _count > 0,
       label: Text('$_count'),
-      backgroundColor: seedGreen,
+      backgroundColor: Theme.of(context).colorScheme.error,
       child: widget.child,
     );
   }