feat(#131): fiches parent/AM éditable, placement AM↔enfant, statuts garde/sans_garde

Squash merge develop → master.

- Fiche parent éditable (co-parent, PATCH fiche, GET /parents)
- Fiche AM 3 onglets (PATCH fiche, rattacher/détacher enfants)
- Table enfants_assistantes_maternelles + enum garde/sans_garde
- Migration SQL + BDD.sql canonique
- Correctifs recette : @Get() parents, DTO fiche AM, fix NIR

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

frontend/lib/models/parent_model.dart

@@ -1,18 +1,65 @@
+import 'package:p_tits_pas/models/parent_child_summary.dart';
 import 'package:p_tits_pas/models/user.dart';
 
 class ParentModel {
   final AppUser user;
+  final AppUser? coParent;
   final int childrenCount;
+  final List<ParentChildSummary> children;
 
-  ParentModel({required this.user, this.childrenCount = 0});
+  ParentModel({
+    required this.user,
+    this.coParent,
+    this.childrenCount = 0,
+    this.children = const [],
+  });
 
   factory ParentModel.fromJson(Map<String, dynamic> json) {
-    final userJson = json['user'] ?? json;
+    final root = Map<String, dynamic>.from(json);
+    final userJson = Map<String, dynamic>.from(root['user'] ?? root);
+    if (root['numero_dossier'] != null && userJson['numero_dossier'] == null) {
+      userJson['numero_dossier'] = root['numero_dossier'];
+    }
     final user = AppUser.fromJson(userJson);
-    final children = json['parentChildren'] as List?;
+
+    AppUser? coParent;
+    final coParentRaw = root['co_parent'];
+    if (coParentRaw is Map) {
+      coParent = AppUser.fromJson(Map<String, dynamic>.from(coParentRaw));
+    }
+
+    final children = _parseChildren(root);
+    final links = root['parentChildren'] ?? root['parent_children'];
+    final linkCount = links is List ? links.length : 0;
+
     return ParentModel(
       user: user,
-      childrenCount: children?.length ?? 0,
+      coParent: coParent,
+      childrenCount: children.isNotEmpty ? children.length : linkCount,
+      children: children,
     );
   }
+
+  static List<ParentChildSummary> _parseChildren(Map<String, dynamic> json) {
+    final children = <ParentChildSummary>[];
+    final seen = <String>{};
+
+    void add(ParentChildSummary? child) {
+      if (child == null || child.id.isEmpty || seen.contains(child.id)) return;
+      seen.add(child.id);
+      children.add(child);
+    }
+
+    final links = json['parentChildren'] ?? json['parent_children'];
+    if (links is List) {
+      for (final link in links) {
+        if (link is! Map) continue;
+        add(ParentChildSummary.fromParentChildLink(
+          Map<String, dynamic>.from(link),
+        ));
+      }
+    }
+
+    return children;
+  }
 }