This skill should be used when the user says "ensure config", "check arn infra config", "arn-infra-ensure-config", "verify arn infra setup", or wants to verify that Arness Infra configuration is present for the current project. This skill is primarily consumed as a reference by entry-point skills (arn-infra-wizard, arn-infra-assess) which read the ensure-config reference as Step 0 before proceeding with their workflow.