Executable amplitude rules

Isolated-copy gate tests (p14r). The test copies contain every frozen input (the top-level directories of frozen_p13_inputs.json, including tests/); the p14 copies lacked tests/, so every copy was unfrozen. The expected outcomes are:

• the unmutated copy has freeze true, and publication is accepted;

• each P.5-only mutation (DRED mutation not rejected, counterterm flag, amplitude mutation) keeps the freeze true, turns the named contract flag false, and is rejected;

• the hard-stop mutations keep the freeze true and are rejected;

• the classical mutations make the freeze false and are rejected.