NWS doesn't publish pressure (its pressure series is empty) or a UV index. When the selected source is NWS, merge current.pressure_msl, current.uv_index and daily.uv_index_max from Open-Meteo and tag them via data._fallback so the Current + Details views show a tooltip noting the value came from the non-selected source (Open-Meteo) instead of showing 0 hPa / --.