AWS health documentation change
Summary
File renamed from 'controlling-access.md' to 'security-iam.md'. Updated PDF anchor reference from '#controlling-access' to '#security-iam'. Minor text change: 'Health Dashboard' to 'AWS Health Dashboard'.
Security assessment
This is a file rename and corresponding reference updates to align with AWS documentation naming conventions. The content change from 'Health Dashboard' to 'AWS Health Dashboard' is a branding/clarity update. There is no evidence of addressing a security vulnerability or adding new security documentation.