feat(#157): alerte enfants sans responsable + rattachement foyer.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/lib/widgets/admin/common/admin_enfant_user_card.dart

@@ -3,6 +3,7 @@ import 'package:p_tits_pas/models/enfant_admin_model.dart';
 import 'package:p_tits_pas/models/parent_child_summary.dart';
 import 'package:p_tits_pas/utils/date_display_utils.dart';
 import 'package:p_tits_pas/utils/enfant_status_utils.dart';
+import 'package:p_tits_pas/utils/enfant_vigilance.dart';
 import 'package:p_tits_pas/widgets/admin/common/admin_user_card.dart';
 
 List<String> enfantAdminSubtitleLines({
@@ -36,6 +37,8 @@ class AdminEnfantUserCard extends StatelessWidget {
   final VoidCallback? onCardTap;
   final EdgeInsetsGeometry? margin;
   final EdgeInsetsGeometry? contentPadding;
+  final Color? borderColor;
+  final String? vigilanceTooltip;
 
   const AdminEnfantUserCard({
     super.key,
@@ -46,6 +49,8 @@ class AdminEnfantUserCard extends StatelessWidget {
     this.onCardTap,
     this.margin,
     this.contentPadding,
+    this.borderColor,
+    this.vigilanceTooltip,
   });
 
   factory AdminEnfantUserCard.fromEnfant(
@@ -55,10 +60,13 @@ class AdminEnfantUserCard extends StatelessWidget {
     VoidCallback? onCardTap,
     EdgeInsetsGeometry? margin,
     EdgeInsetsGeometry? contentPadding,
+    Color? borderColor,
+    String? vigilanceTooltip,
   }) {
     final parents = enfant.parentLinks
         .map((l) => l.parentName ?? 'Parent')
         .join(', ');
+    final orphan = enfantHasNoResponsable(enfant);
     return AdminEnfantUserCard(
       title: enfant.fullName,
       photoUrl: enfant.photoUrl,
@@ -69,6 +77,7 @@ class AdminEnfantUserCard extends StatelessWidget {
         gender: enfant.gender,
         extra: [
           if (parents.isNotEmpty) 'Responsables : $parents',
+          if (orphan) 'Aucun responsable rattaché',
           ...extraSubtitleLines,
         ],
       ),
@@ -76,6 +85,10 @@ class AdminEnfantUserCard extends StatelessWidget {
       onCardTap: onCardTap,
       margin: margin,
       contentPadding: contentPadding,
+      borderColor: borderColor ??
+          (orphan ? Colors.red.shade300 : null),
+      vigilanceTooltip: vigilanceTooltip ??
+          enfantSansResponsableVigilanceMessage(enfant),
     );
   }
 
@@ -114,6 +127,8 @@ class AdminEnfantUserCard extends StatelessWidget {
       onCardTap: onCardTap,
       margin: margin,
       contentPadding: contentPadding,
+      borderColor: borderColor,
+      vigilanceTooltip: vigilanceTooltip,
     );
   }
 }