Add new OpenAPINormalizer rule SORT_MODEL_PROPERTIES that sorts schema
properties alphabetically by name. This ensures deterministic code
generation output regardless of property ordering in the source spec.
The rule:
- Uses TreeMap to sort properties by natural string order
- Applies at the OpenAPI normalization stage, working for all generators
- Is opt-in (defaults to false) to maintain backward compatibility
Usage:
openapi-generator generate --openapi-normalizer SORT_MODEL_PROPERTIES=true ...
Fixes non-deterministic property ordering that could cause spurious diffs
in generated code when the source schema order varies.
f7ac63a188