The library behind [rekey](https://github.com/Ezra-Black/rekey): provider
connectors (AWS, GitLab, Cloudflare, Datadog, npm, Docker Hub, OpenAI,
Anthropic, Twilio, SendGrid, GitHub App), the rotation engine, consumers
(.env, GitHub Actions secrets, AWS SSM, files, OS keychain), and config.
Most people want the CLI: `cargo install rekey`.