Arn Infra Define

- This skill should be used when the user says "define infrastructure", "generate IaC", "infra define", "arn infra define", "generate terraform", "generate opentofu", "generate pulumi", "generate cdk", "generate bicep", "create kubernetes manifests", "provision cloud resources", "create IaC", "infrastructure as code", or wants to generate infrastructure-as-code in their chosen IaC tool for configured cloud provider(s). It produces provider-specific infrastructure code, validates it through a multi-level validation ladder, and writes an infrastructure architecture spec.