Function containers_document 

pub fn containers_document(
    reports: &[EngineReport],
    kubernetes_contexts: &[String],
) -> Value

The document emitted by devp caches docker --json and its siblings.

Deliberately has no clear_command anywhere, unlike caches_document. The prune commands are in the human report because a person reads them and decides; putting them in a machine-readable document would be handing an agent an argv for docker system prune --volumes, and no field in this contract should be one command substitution away from deleting a database. An agent that wants to reclaim container disk should say so to its human.

kubernetes_contexts carries names and no sizes, for the same reason the table does: a local cluster’s disk already belongs to one of the engines above.