Update changelog

Author: ali-sedaghatbaf

CHANGELOG.md

@@ -6,6 +6,10 @@
 
 - MarkdownLoader (experimental): added a Markdown loader to support `.md` and `.markdown` files.
 
+### Fixed
+
+- `NodeType`: a node type defined without a `properties` key (e.g. `{"label": "Person"}` or `{"label": "Person", "description": "..."}`) now automatically gets a default `name: STRING` property and `additional_properties=True`, preventing a `ValidationError` from the `min_length=1` constraint. This matches the existing behaviour for string input. Auto-addition is skipped when `properties` is explicitly provided (including as an empty list) or when `additional_properties` is explicitly set to `False`.
+
 ### Changed
 
 - SimpleKG pipeline (experimental): the `from_pdf` parameter is deprecated in favor of `from_file` (PDF and Markdown inputs). `from_pdf` still works but emits a deprecation warning and will be removed in a future version.