059-datazone: document IAM Identity Center prereq for environment profiles

Author: mwunderl

tuts/059-amazon-datazone-gs/REVISION-HISTORY.md

@@ -10,3 +10,7 @@
 - Type: functional
 - security and consistency updates
 
+
+### 2026-04-29 note
+- Type: documentation
+- CreateEnvironmentProfile requires IAM Identity Center integration with DataZone. The domain owner IAM user alone cannot create environment profiles without SSO configured. This is a service prereq, not a script bug.