feat(#156): création dossier AM staff — API + wizard dashboard.

Squash depuis develop : POST /assistantes-maternelles/dossier (actif +
mail MDP), AmDossierWizard create/review, validations inscription.

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

frontend/lib/widgets/admin/validation_dossier_modal.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:p_tits_pas/models/dossier_unifie.dart';
 import 'package:p_tits_pas/services/user_service.dart';
+import 'package:p_tits_pas/widgets/admin/am_dossier_wizard.dart';
 import 'package:p_tits_pas/widgets/admin/validation_am_wizard.dart';
 import 'package:p_tits_pas/widgets/admin/validation_family_wizard.dart';
 
@@ -76,8 +77,13 @@ class _ValidationDossierModalState extends State<ValidationDossierModal> {
 
   /// Largeur modale = 1,5 × 620.
   static const double _modalWidth = 930; // 620 * 1.5
-  // Hauteur uniforme (ajustée +5px pour éviter l'overflow des étapes parents sans scroll).
-  static const double _bodyHeight = 435;
+  static const double _familyBodyHeight = 435;
+
+  double get _bodyHeight {
+    final d = _dossier;
+    if (d != null && d.isAm) return AmDossierWizard.shellBodyHeight;
+    return _familyBodyHeight;
+  }
 
   @override
   Widget build(BuildContext context) {