Follow-up to the #67690 salvage (@m4r13y). The PR's tools/env_probe.py
hunk was written against the old capture_output=True _run(); #67964/#67999
rewrote _run to temp-file capture on July 20, so that hunk no longer
applied — but the rewritten _run still lacked creationflags and kept
flashing one console per probe (~5 per kanban worker start) from
windowless parents. Re-implement the one-line fix against the current
shape: creationflags=windows_hide_flags() on the temp-file subprocess.run,
preserving the #67964 grandchild-can't-wedge-the-pipe contract.
Also add the tests the PR didn't ship, in
tests/test_windows_subprocess_no_window_flags.py:
- env_probe._run passes CREATE_NO_WINDOW and keeps temp-file (non-PIPE)
stdout/stderr + DEVNULL stdin
- lazy_deps uv install / pip --version probe / pip install fallback /
ensurepip bootstrap all pass CREATE_NO_WINDOW
- suppress_platform_ver_console: POSIX no-op (platform._syscmd_ver
untouched, win32_ver() still returns), and simulated-Windows stubbing
(echo stub installed, idempotent, never raises)
0b17d4d71e