Deployment package flow
A deployment workspace can express ordering without shell scripts:
The executor is expected to schedule all currently-ready operations in parallel.
The example has one serial chain (repo -> package -> archive), but unrelated steps
such as docs generation, checksums, or metadata generation may share the same prior
dependency and run concurrently.
Temporary convenience form
workspace.temp(...) means: allocate an execution-scoped ??/ root, execute the
operation with that root bound, capture bounded output/result metadata, then cleanup.
It does not mean std::env::temp_dir() is directly exposed to REL.