feat(#159/#160): suppressions métier dashboard — API + UI (squash develop).

Matrice PO #154 : supprimer dossiers famille/AM, parents, enfants et comptes
staff avec règles métier (placements clôturés, sans_enfant, cascade foyer,
droits gestionnaire/admin). Poubelle en liste, dialogues de confirmation,
garde-fou gestionnaire→gestionnaire. Inclut polish hauteur modale fiche AM.

frontend/lib/widgets/admin/parent_managmant_widget.dart

@@ -1,8 +1,12 @@
 import 'package:flutter/material.dart';
+import 'package:p_tits_pas/models/dossier_list_item.dart';
 import 'package:p_tits_pas/models/parent_model.dart';
+import 'package:p_tits_pas/services/auth_service.dart';
 import 'package:p_tits_pas/services/user_service.dart';
+import 'package:p_tits_pas/utils/staff_deletion_rights.dart';
 import 'package:p_tits_pas/widgets/admin/common/admin_parent_edit_modal.dart';
 import 'package:p_tits_pas/widgets/admin/common/admin_user_card.dart';
+import 'package:p_tits_pas/widgets/admin/common/suppression_confirm_dialog.dart';
 import 'package:p_tits_pas/widgets/admin/common/user_list.dart';
 
 class ParentManagementWidget extends StatefulWidget {
@@ -23,16 +27,24 @@ class _ParentManagementWidgetState extends State<ParentManagementWidget> {
   bool _isLoading = false;
   String? _error;
   List<ParentModel> _parents = [];
+  bool _canDelete = false;
 
   @override
   void initState() {
     super.initState();
+    _loadRights();
     _loadParents();
   }
 
   @override
   void dispose() => super.dispose();
 
+  Future<void> _loadRights() async {
+    final user = await AuthService.getCurrentUser();
+    if (!mounted) return;
+    setState(() => _canDelete = canDeleteMetier(user?.role));
+  }
+
   Future<void> _loadParents() async {
     setState(() {
       _isLoading = true;
@@ -54,6 +66,67 @@ class _ParentManagementWidgetState extends State<ParentManagementWidget> {
     }
   }
 
+  bool _isLastParent(ParentModel parent) {
+    final co = parent.coParent?.id.trim();
+    if (co != null && co.isNotEmpty) return false;
+    final num = (parent.user.numeroDossier ?? '').trim();
+    if (num.isEmpty) return true;
+    return !_parents.any((other) {
+      if (other.user.id == parent.user.id) return false;
+      return (other.user.numeroDossier ?? '').trim() == num;
+    });
+  }
+
+  Future<void> _confirmDelete(ParentModel parent) async {
+    final num = (parent.user.numeroDossier ?? '').trim();
+    final name = formatDossierPersonLabel(
+      nom: parent.user.nom,
+      prenom: parent.user.prenom,
+      email: parent.user.email,
+    );
+    final last = _isLastParent(parent);
+    final enfants = ParentModel.foyerChildrenCount(parent, _parents);
+    final footnotes = last
+        ? <String>[
+            if (num.isNotEmpty) 'Dernier parent du dossier $num.',
+            if (num.isEmpty) 'Dernier parent du dossier.',
+            'Les $enfants enfant(s) rattaché(s) seront aussi supprimés.',
+          ]
+        : <String>[
+            if (num.isNotEmpty)
+              'Ce parent sera retiré du dossier $num.',
+            'Les enfants restent avec le co-parent.',
+          ];
+
+    final confirmed = await showSuppressionConfirmDialog(
+      context,
+      title: 'Supprimer le parent',
+      subtitle: num.isEmpty ? null : 'Dossier $num',
+      people: [SuppressionPersonLine.parent(name)],
+      footnotes: footnotes,
+    );
+    if (!confirmed || !mounted) return;
+
+    try {
+      final result = await UserService.deleteUser(parent.user.id);
+      if (!mounted) return;
+      final msg = (result['message'] ?? 'Parent supprimé.').toString();
+      ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text(msg)));
+      await _loadParents();
+    } catch (e) {
+      if (!mounted) return;
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(
+          content: Text(
+            e is Exception
+                ? e.toString().replaceFirst('Exception: ', '')
+                : 'Erreur suppression',
+          ),
+        ),
+      );
+    }
+  }
+
   @override
   Widget build(BuildContext context) {
     final query = widget.searchQuery.toLowerCase();
@@ -90,6 +163,8 @@ class _ParentManagementWidgetState extends State<ParentManagementWidget> {
                 _openParentDetails(parent);
               },
             ),
+            if (_canDelete)
+              suppressionIconButton(onPressed: () => _confirmDelete(parent)),
           ],
         );
       },