Historical PLUMB v1 examples

These files preserve the former Field-sized authorization schema for review. They are unsafe prototypes: authorization has at most one field of entropy, independent membership paths do not establish an atomic tree update, and Card mint/burn/config checks were incomplete. Do not deploy or benchmark them as complete contracts. The maintained version is PLUMB v2 in examples/neptune/standards/, specified by Trident reference/plumb-v2.md.