Remove guppylang dev dependency

Now that selene is consumed _by_ guppylang, it's time that we start peeling guppylang dependency away from Selene itself. This will remove a bunch of problems that we currently have regarding dependency cycles and pollution of transitives.

We can use the approach taken in tket2's hugr-qis-compiler - use `uv` scripts to generate hugr (or even qis directly) and use _those_ for testing and examples.