## Why
`codex-utils-pty` and `codex-windows-sandbox` were the remaining crates
in `codex-rs` that still overrode the workspace's Rust 2024 edition.
Moving them forward in a separate PR keeps the baseline edition update
isolated from the follow-on Bazel clippy workflow in #15955, while
making linting and formatting behavior consistent with the rest of the
workspace.
This PR also needs Cargo and Bazel to agree on the edition for
`codex-windows-sandbox`. Without the Bazel-side sync, the experimental
Bazel app-server builds fail once they compile `windows-sandbox-rs`.
## What changed
- switch `codex-rs/utils/pty` and `codex-rs/windows-sandbox-rs` to
`edition = "2024"`
- update `codex-utils-pty` callsites and tests to use the collapsed `if
let` form that Clippy expects under the new edition
- fix the Rust 2024 fallout in `windows-sandbox-rs`, including the
reserved `gen` identifier, `unsafe extern` requirements, and new Clippy
findings that surfaced under the edition bump
- keep the edition bump separate from a larger unsafe cleanup by
temporarily allowing `unsafe_op_in_unsafe_fn` in the Windows entrypoint
modules that now report it under Rust 2024
- update `codex-rs/windows-sandbox-rs/BUILD.bazel` to `crate_edition =
"2024"` so Bazel compiles the crate with the same edition as Cargo
---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/openai/codex/pull/15954).
* #15976
* #15955
* __->__ #15954
## Summary
- launch Windows sandboxed children on a private desktop instead of
`Winsta0\Default`
- make private desktop the default while keeping
`windows.sandbox_private_desktop=false` as the escape hatch
- centralize process launch through the shared
`create_process_as_user(...)` path
- scope the private desktop ACL to the launching logon SID
## Why
Today sandboxed Windows commands run on the visible shared desktop. That
leaves an avoidable same-desktop attack surface for window interaction,
spoofing, and related UI/input issues. This change moves sandboxed
commands onto a dedicated per-launch desktop by default so the sandbox
no longer shares `Winsta0\Default` with the user session.
The implementation stays conservative on security with no silent
fallback back to `Winsta0\Default`
If private-desktop setup fails on a machine, users can still opt out
explicitly with `windows.sandbox_private_desktop=false`.
## Validation
- `cargo build -p codex-cli`
- elevated-path `codex exec` desktop-name probe returned
`CodexSandboxDesktop-*`
- elevated-path `codex exec` smoke sweep for shell commands, nested
`pwsh`, jobs, and hidden `notepad` launch
- unelevated-path full private-desktop compatibility sweep via `codex
exec` with `-c windows.sandbox=unelevated`
