probe-output.schema: derive the machine.class and machine.profile field names from the contract (MACHINE_CLASS_FIELDS, MACHINE_PROFILE_FIELDS) #122

The field names of machine.class and machine.profile in protocol/probe-output.schema.in match the contract's MACHINE_CLASS_FIELDS and MACHINE_PROFILE_FIELDS exactly today but are still typed by hand in the template (#120 derived the five shared enums). Take them as tokens the same way (generator fill from omx_vocabulary.h plus a test-vocabulary arm and a sabotage). Ruling: coordinator, 2026-10-20 (comment on #120).