This fixture demonstrates the Milestone 2 `.api` flow:
```bash
rs-zero api validate -f examples/api-hello/hello.api
rs-zero api openapi -f examples/api-hello/hello.api -o examples/api-hello/openapi.json
rs-zero api gen -f examples/api-hello/hello.api -d target/generated
```
The supported DSL subset is documented in `docs/api-dsl.md`.