GitHub's Windows runners set TEMP to the 8.3 short form
(C:\Users\RUNNER~1\...), and every path that goes through git or realpath
comes back in the long form, so equality checks between a temp directory and
its canonical form fail. A shared setup file, run by every package's vitest
config, points TEMP/TMP at the long form once so os.tmpdir() and everything
built on it agree with the canonical spelling.

bootstrap.test opens the platform null device instead of /dev/null and skips
the FIFO case, since Windows has neither.

Co-Authored-By: Claude Code <noreply@anthropic.com>