Add create-meta-recipe endpoint with nested slots/options/bases

- POST /api/create-meta-recipe/ creates full meta-recipe in one call
- PUT /api/create-meta-recipe/ updates existing (requires id)
- Auto-resolves ingredients by name/alias, creates new if not found
- Returns full nested response with _created_ingredients list
- New writable serializers: MetaRecipeWriteSerializer, SlotWriteSerializer, etc.

kitchen/urls.py

@@ -22,4 +22,5 @@ urlpatterns = [
     path("bulk-pantry-add/", views.bulk_pantry_add, name="bulk-pantry-add"),
     path("generate-shopping-list/", views.generate_shopping_list, name="generate-shopping-list"),
     path("import-recipe/", views.import_recipe_url, name="import-recipe"),
+    path("create-meta-recipe/", views.create_meta_recipe, name="create-meta-recipe"),
 ]