feat(#112): aligner reprise front sur dossier complet GET/PATCH

Préremplit parents, enfants, motivation et fiche AM depuis reprise-dossier
et envoie le body PATCH complet (co-parent, enfants par id, champs pro AM).

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

frontend/lib/services/auth_service.dart

@@ -291,43 +291,20 @@ class AuthService {
   }
 
   /// Resoumission après refus. PATCH /auth/reprise-resoumettre. Ticket #112.
-  static Future<void> resoumettreReprise({
-    required String token,
-    String? prenom,
-    String? nom,
-    String? telephone,
-    String? adresse,
-    String? ville,
-    String? codePostal,
-    String? photoUrl,
-  }) async {
-    final cleaned = token.trim();
+  static Future<void> resoumettreReprise(Map<String, dynamic> body) async {
+    final cleaned = body['token']?.toString().trim() ?? '';
     if (cleaned.isEmpty) {
       throw Exception('Lien invalide ou expiré.');
     }
-    final body = <String, dynamic>{'token': cleaned};
-    if (prenom != null && prenom.trim().isNotEmpty) body['prenom'] = prenom.trim();
-    if (nom != null && nom.trim().isNotEmpty) body['nom'] = nom.trim();
-    if (telephone != null && telephone.trim().isNotEmpty) {
-      body['telephone'] = telephone.trim();
-    }
-    if (adresse != null && adresse.trim().isNotEmpty) {
-      body['adresse'] = adresse.trim();
-    }
-    if (ville != null && ville.trim().isNotEmpty) body['ville'] = ville.trim();
-    if (codePostal != null && codePostal.trim().isNotEmpty) {
-      body['code_postal'] = codePostal.trim();
-    }
-    if (photoUrl != null && photoUrl.trim().isNotEmpty) {
-      body['photo_url'] = photoUrl.trim();
-    }
+    final payload = Map<String, dynamic>.from(body);
+    payload['token'] = cleaned;
 
     late final http.Response response;
     try {
       response = await http.patch(
         Uri.parse('${ApiConfig.baseUrl}${ApiConfig.repriseResoumettre}'),
         headers: ApiConfig.headers,
-        body: jsonEncode(body),
+        body: jsonEncode(payload),
       );
     } on http.ClientException {
       throw Exception(