## Why
We want to make it possible for an app-server orchestrator on one OS to
control an exec-server on another host running a different OS. In
practice this kinda already works if you get lucky and the two hosts
have the same path format, but we mangle quite a lot of operations if
either end is Windows.
This test starts exercising that interaction, although right now the
initial bootstrap fails. Future changes will expand the test's
assertions to match improved support.
## What
Stacked on #27964. This adds a small Windows exec-server fixture and a
Linux protocol smoke test using the reusable Wine harness, covering
Windows environment discovery, non-TTY `cmd.exe` execution, output, exit
status, and working directory.
Once we've got the full codex binary cross-building under Bazel we could
consider moving to the real binary instead of the stripped down
exec-server-only binary used here.
## Why
We want to make it possible for an app-server orchestrator on one OS to
control an exec-server on another host running a different OS. In
practice this kinda already works if you get lucky and the two hosts
have the same path format, but we mangle quite a lot of operations if
either end is Windows.
We should be able to test the cross-platform interactions for
exec-server, but we want to do this fairly soon and need a lightweight
option for testing. Using Wine to run the Windows side is far from
perfect, but it should give us a decent measure of how well we're
handling the basics of paths, process spawning, shell interaction, etc.
Future changes will add actual exec-server tests and possibly extensions
to the Wine testing environment.
## What
To make the cross-target-triple build easy, these tests are added only
to the Bazel build. This change adds an x86_64 Wine prebuilt managed by
Bazel and some build rules that can set up the needed toolchain
transition.
The support library for running Wine in a test environment created by
the Bazel rules comes with its own basic unit and integration tests.
Their primary priority is to make sure we don't leak child processes on
developer machines and that we can build and launch a basic hello world
binary.
## Validation
Confirmed these new tests are running on the [x86_64 bazel ubuntu
jobs](https://github.com/openai/codex/actions/runs/27446432302/job/81132356855?pr=27937):
```
//bazel/rules/testing/wine:wine-smoke-test (cached) PASSED in 3.7s
//bazel/rules/testing/wine:wine-test-support-unit-tests (cached) PASSED in 15.8s
```
## Intent
Keep release-specific Bazel helpers out of the shared Rust crate
definitions and colocate them with Bazel platform configuration.
## Implementation
Moves `multiplatform_binaries` and its platform list from `defs.bzl`
into `bazel/platforms/release_binaries.bzl` and updates the CLI load
site. Behavior is unchanged.
## Validation
- `bazel query //codex-rs/cli:release_binaries`
Stack: 1 of 6.
