Advanced AI Prompt for Ephemeral Environment Provisioning per PR

Act as a Developer Experience (DX) Architect. Create a dynamic GitHub Actions workflow that physically provisions completely isolated, ephemeral 'preview' environments for every single open Pull Request. The workflow must execute Terraform or AWS CDK to spin up full [CLOUD_RESOURCES] (e.g., isolated RDS databases, independent Kubernetes Namespaces, or ECS tasks). The workflow must rigorously tag every provisioned asset with the exact [PR_NUMBER] and inject a metadata tag enforcing a strict [TTL_DURATION] (e.g., 24 hours). Crucially, engineer a secondary, parallel 'Teardown' workflow that listens exclusively for the [CLEANUP_TRIGGER] (e.g., `pull_request: types: [closed, merged]`) to aggressively destroy the specific resources matching the PR tag, preventing massive cloud billing leaks.