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>

backend/src/routes/parents/parents.mapper.ts

@@ -0,0 +1,18 @@
+import { Parents } from 'src/entities/parents.entity';
+import { sanitizeUserForApi } from '../../common/utils/sanitize-user-for-api';
+
+/**
+ * Sérialisation API fiche parent — ticket #131.
+ * Garantit `user`, `co_parent` (si présent) et relations sans champs sensibles.
+ */
+export function mapParentForApi(parent: Parents): Parents {
+  return {
+    ...parent,
+    user: sanitizeUserForApi(parent.user)!,
+    co_parent: sanitizeUserForApi(parent.co_parent),
+  };
+}
+
+export function mapParentsForApi(parents: Parents[]): Parents[] {
+  return parents.map(mapParentForApi);
+}