The cancel-tool-calls scenario cancels a live bash call, which relies on
POSIX detached-process-group termination; bash has no Windows process-tree
kill yet (deferred with the Bash execution domain), so the hung call times
the scenario out on the native Windows snapshot lane.
Add a posixOnly scenario declaration that skips the run test on win32
while the fixture guards keep covering committed files on every platform,
and mark cancel-tool-calls with it.
imccyu
5faf8d1200