zena:host-setup

What a program on the zena command's host needs installed before it runs, for the zena-cli target: Error's stack traces, from zena-cli:host/stack-trace as the compiler synthesizes it from the host's WIT, installed into zena:core through the hooks in core/error/stack-hooked.zena.

Loaded as one of the target's runtime modules, and installHost is called by the component entry before the program's main: the hooks exist because Error cannot import this module — everything here imports zena:core back — and the entry calls it because a runtime module has no other way to run before the program does.