Snapshot diagnostic state for a hung `pytest`/`tractor`
process tree: for each pid (+ `pgrep -P` descendants) dump
the `ps` forest, `/proc/<pid>/wchan` + `stack` (kernel-side
blocked syscall), and `py-spy dump` (python-side stack).
Salvaged from the retired `wkt/warnings_cleanup` branch
(untracked, not upstream); homed here as standalone tooling.
(this commit msg was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
Gud Boi