MeasurementContainer.isUnitCompatible now short-circuits to accept any unit
when the measurement type is not in the built-in measureMap. Known types
(pressure, flow, power, temperature, volume, length, mass, energy) still
validate strictly. This unblocks user-defined types in the measurement
node's new digital/MQTT mode — e.g. 'humidity' with unit '%', 'co2' with
'ppm' — without forcing those units into the convert-module unit system.
measurement.json schema: add 'mode.current' (analog | digital) and
'channels' (array) so the validator stops stripping them from the runtime
config. Ignored in analog mode.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
