pilotr 0.2.0

Adds pilotr_example() to both twins. It lists the design specifications shipped with the package, one per design family, and returns the path to each for load_spec().

The eight per-family JSON specifications now travel inside each package (r/pilotr/inst/examples/ and the Python wheel), so an installed copy can load them without a checkout of the repository. R gains a Worked examples article that simulates every one, matching the Python page.

Both twins move to 0.2.0. See NEWS.md and CHANGELOG.md.