fix(pm): net ci-failure.mjs's walk against mid-walk transport failures (#10361)

A transport failure arriving after the pre-walk probe passed escaped as an
uncaught throw, and node's exit 1 collides with this file's own EXIT_RED --
so a container that read nothing about the tree handed its caller the code
that means "the tree is red and here is the proof".

Every network read after the probe is now wrapped. The exit-2-vs-3 fork is
settled by re-probing rather than by picking a constant: an unusable fresh
reading is the environment (3), a healthy one is a walk that cannot answer
(2), and an unclassifiable one falls to 2 rather than blaming the container.
Never 1, never 0.

The partial-output invariant rides along, twice: the net's report says
whether nothing was READ or nothing was JUDGED and counts what had been
listed, and assertionStatus gains a fourth answer so a refused annotations
call stops printing as "the check carried no annotation with any content in
it" -- four lines under this same block's own disclaimer.

Fixes #10155


Claude-Session: https://claude.ai/code/session_01DdCnBGcHeufjrq7drTD3wt

Co-authored-by: Claude <noreply@anthropic.com>

Author: os-zhuang