Module command 

Command hook handler — feeds the step envelope JSON to an external subprocess. The IO protocol passes stdout through as verdict JSON.

Shape

• CommandSpec: handler configuration — either direct argv spawn or explicit shell.
• CommandHandler: implements StepHandler; spawn / kill_on_drop / timeout follow the documented semantics.

No shell dependency: direct argv spawn is the default; only the explicit shell field uses a shell.

Platform fallback: on cfg(unix) and cfg(windows), spawns the child process via tokio::process::Command.

Structs

CommandHandler

Command handler implementation.

Enums

CommandSpec

Configuration for a command handler.

ShellKind

Explicit shell kind. The engine uses this tag to select the executable and its flag.