Register Machines: Polyrate (and DirDyVTST) still listed among the codes #350

Found 2026-10-15 (Linux, test-912 build). Reaction studies are no longer offered under New (#331), but Register Machines still lists Polyrate among the codes a machine can run. Retired codes should not be offered there either. Check DirDyVTST and the other retired codes in the same list. Not release-critical.