sanitize_json() called `python3` unconditionally, but on ACG Windows boxes
the Microsoft Store python3 alias is disabled and `py` is the launcher
(feedback_python_windows). When `python3` was missing the function silently
returned empty, and the surrounding `result_safe='{"messages":[]}'` default
dropped every unread coord message — no error, no warning, no toast.
Now prefers identity.json's `.python.command` (set during machine onboarding,
matching the pattern other scripts already use), falls back to
`command -v python3 || command -v py || command -v python`, and if no Python
is available falls back to `tr -d '\000-\037'` so jq can still parse — lossy
on real \n/\t in string fields but keeps messages visible instead of dropping
them.
Mike Swanson
93d24815c1