## Why
`provider_auth_command_supplies_bearer_token` and
`provider_auth_command_refreshes_after_401` were still flaky under
Windows Bazel because the generated fixture used `powershell.exe`, whose
startup can be slow enough to trip the provider-auth timeout in CI.
## What
Replace the generated Windows auth fixture script in
`codex-rs/core/tests/suite/client.rs` with a small `.cmd` script
executed by `cmd.exe /D /Q /C`, and advance `tokens.txt` one line at a
time so the refresh-after-401 test still gets the second token on the
second invocation.
Also align the fixture timeout with the provider-auth default (`5_000`
ms) to avoid introducing a test-only timing budget that is stricter than
production behavior.
## Testing
Left to CI, specifically the Windows Bazel
`//codex-rs/core:core-all-test` coverage for the two provider-auth
command tests.
Michael Bolin
3a22e10172