fix: IO.Process.spawn on windows

[Rob23oba]

This PR fixes a resource leak and a command quoting issue in IO.Process.spawn. Previously, only file handles for pipes were closed and only when creating a process succeeded.

Closes #8547
Closes #8597

[leanprover-community-bot]

Mathlib CI status (docs):

• ❗ Batteries/Mathlib CI will not be attempted unless your PR branches off the nightly-with-mathlib branch. Try git rebase 3ccc9ca7ac86504e100a39066e0c83443a57d047 --onto 0f4459b42c87d7712391e6d87160da3077fff671. You can force Mathlib CI using the force-mathlib-ci label. (2025-06-03 15:26:43)

[Kha]

Thanks for the PR. Have you checked whether libuv covers this?

[Rob23oba]

Hmm it seems like https://docs.libuv.org/en/v1.x/process.html#c.uv_stdio_container_t does something similar to what we need but I didn't look too much into the details