New 'Current energy / lambda' row above the setpoint, fed per DAQ
tick from diffraction.energy_keV; the setpoint row is renamed
'Set Energy (keV)' so 'what is' and 'what to set' are distinct.
Guards energy 0.0 (server's detector-unavailable fallback) because
the wavelength property divides by it. The copied energy row in the
experiment configuration is renamed to match.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>