## 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.
Adam Perry @ OpenAI