Skrog wslkit

Skrog serves the real Docker Engine API on the named pipe docker.exe already talks to, backed by upstream dockerd running in a WSL2 distro it owns. Compose, Dev Containers, Testcontainers, buildx and the Docker CLI work unmodified, because the thing answering is genuinely dockerd. It is headless by design: no GUI, no Kubernetes, no tray ceremony, and no licence fee. A supervisor starts the engine at logon, survives crashes, `wsl --shutdown` and sleep/resume, and idle-stops the engine to return its RAM. `skrog lock` pins the exact dockerd, containerd, runc and BuildKit commits so a laptop and a CI runner install the same engine. Installing this package places the skrog command on PATH. It does not provision anything: run `skrog install` next to set up the engine, then `skrog start`. Skrog does not install a docker CLI - use Docker Desktop's, or `skrog cli install`.