fix: primary output of the codex-cli crate is named codex, not codex-cli (#743)

I just got a bunch of failures in the release workflow:

https://github.com/openai/codex/actions/runs/14745492805/job/41391926707

along the lines of:

```
cp: cannot stat 'target/aarch64-unknown-linux-gnu/release/codex-cli': No such file or directory
```

.github/workflows/rust-release.yml

@@ -104,7 +104,7 @@ jobs:
 
           cp target/${{ matrix.target }}/release/codex-repl "$dest/codex-repl-${{ matrix.target }}"
           cp target/${{ matrix.target }}/release/codex-exec "$dest/codex-exec-${{ matrix.target }}"
-          cp target/${{ matrix.target }}/release/codex-cli "$dest/codex-cli-${{ matrix.target }}"
+          cp target/${{ matrix.target }}/release/codex "$dest/codex-${{ matrix.target }}"
 
       - if: ${{ matrix.target == 'x86_64-unknown-linux-musl' }} || ${{ matrix.target == 'aarch64-unknown-linux-gnu' }}
         name: Stage Linux-only artifacts