docs: add Features section to CHANGELOG for CreateUserIdentity identity_id fix

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

Author: BrandtKruger

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+### Features
+
+- **Management API (generated):** Added `EffectiveIdentityID()` helper method to `CreateIdentityResponseIdentity`. The decoder now handles both `id` and `identity_id` JSON keys when creating identities, accommodating the API's alternate field name for existing enterprise identities.
+
 ### Breaking changes
 
 - **Management API (generated):** Response types for the delete API application scope operation were renamed to fix a typo: `DeleteAPIAppliationScope*` → `DeleteAPIApplicationScope*` (e.g. `DeleteAPIAppliationScopeBadRequest` → `DeleteAPIApplicationScopeBadRequest`). If you reference the old type names in your code, update them to the new spelling.