- Remove duplicate shebang, set -e, and redundant SSM agent install from user data
script so cfn-signal always runs (root cause of "0 SUCCESS signals" deploy failure)
- Remove DNS record creation from service stack's configureBlueGreenDns() to avoid
CloudFormation conflicts with the persistent ALB stack that owns those records
- Replace readonly type assertion hacks with direct property assignments on 6 ALB/listener fields
- Change default health check path from /health to / for universal compatibility
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
