Hand-encoded byte sequences for RadioConfig, every Command tag, and
every Response tag, taken directly from the spec. Fields use hex-clean
values (freq_hz = 0x12345678, sync_word = 0xABCD, etc.) so each
little-endian byte is visually verifiable.
Locks firmware and host to the written spec — a refactor that quietly
changes a field layout fails here, not in the field.
