Machine-generated by `cli::emit_rust_code` (verified shape V1): the exact
builder equivalent of
```bash
ffmpeg -i in.mkv -c:v libx264 -crf 23 -preset fast -c:a aac -y out.mp4
```
`main.rs` is pinned byte-for-byte against the emitter by a unit test — do not
hand-edit it; regenerate with `cli::emit_rust_code` if the emitter changes.
```bash
cargo run --example cli_emitted_transcode
```
Expects an `in.mkv` in the working directory.