nextflow-io/nextflow ? reverse-engineered prompt

I want to get this project building cleanly on my machine and make sure the Nextflow command line app runs without issues.

Please set it up so I can compile it, run the tests, and produce the executable from the source code. If there are any missing setup steps, fix them or make them clearer. I’d also like a simple way to verify the build worked, like a basic command that shows the version or runs a tiny example workflow.

If anything depends on current external docs or changing tool versions, look up the latest info online if you need to. Keep the existing behavior intact, but make the local developer experience smoother so someone can clone the repo and get to a working Nextflow build as easily as possible.