Advanced AI Prompt for Blue-Green Deployment on AWS ECS

Act as a Senior AWS Solutions Architect. Generate a sophisticated GitHub Actions workflow orchestrating a zero-downtime Blue-Green deployment to AWS ECS. Workflow requirements: 1) Build, tag, and push a new Docker image to ECR. 2) Dynamically render the new image URI into the existing ECS [TASK_DEFINITION] JSON template. 3) Utilize `aws-actions/amazon-ecs-deploy-task-definition` to trigger the CodeDeploy Blue-Green routing shift for [SERVICE_NAME] within [CLUSTER_NAME]. 4) Integrate a strict `wait-for-service-stability` parameter to ensure the new tasks are fully healthy before draining the old connections. 5) Include an automated post-deployment step to purge untagged or old images in ECR to optimize storage costs.