Set up secrets management

Set up a secrets management solution for a [Language] application deployed on [Platform]. Use [HashiCorp Vault / AWS Secrets Manager / Azure Key Vault / GCP Secret Manager] as the backend. Show how to fetch and inject secrets into the application at runtime without ever baking them into container images or config files. Demonstrate zero-downtime secret rotation so new credentials can replace old ones without restarting the service, and implement access auditing so every secret read is logged.