Experimental
Build a Docker-backed ContainerRuntime. The two real-IO seams default to the real docker CLI + a real TCP probe, but both are injectable so the lifecycle is unit-testable with fakes.
Optional
Readiness deadline; injectable so a test can cover the timeout path.
Build a Docker-backed ContainerRuntime. The two real-IO seams default to the real docker CLI + a real TCP probe, but both are injectable so the lifecycle is unit-testable with fakes.