interface SnapshotCreateParamsDescription says what this snapshot's image can do, so a caller can hand it to an agent as a capability summary. At most 1024 characters.
Labels seed the snapshot's labels, overriding any label of the same key derived from the Docker image.
RunConfig overrides the runtime configuration taken from the Docker image. Every sandbox created from the snapshot runs as the image's USER, in its WORKDIR, with its ENV beneath the sandbox's own env_vars; user and work_dir given here replace the image's, and env_vars merge over it.
mutable Docker-style tag; defaults to "latest"