setHamMode
Enables amateur-radio (ham) mode on a node via AdminMessage.set_ham_mode.
Must target only the locally connected node — firmware ham onboarding is a local operation; the implementation ignores requests for any other node. The firmware handler rewrites the owner (long_name = call_sign), flips is_licensed, disables encryption, applies HamParameters.tx_power/HamParameters.frequency to the LoRa config verbatim, and reboots. The implementation echoes the local node's current LoRa values into those two fields so a re-send never wipes the node's overrides; caller-supplied HamParameters.tx_power/HamParameters.frequency are ignored. Intentionally absent from AdminEditScope: ham enablement is not a batch-edit operation.