Updated model and normalizers to map provider “feels like” fields into a single ApparentTemperatureC field.

internal/normalizers/nws/observation.go

@@ -80,6 +80,14 @@ func buildObservation(parsed nwsObservationResponse) (model.WeatherObservation,
 	// NWS observation responses typically do not include a day/night flag -> nil.
 	canonicalText := standards.WMOText(wmo, nil)
 
+	// Apparent temperature: prefer wind chill when both are supplied.
+	var apparentC *float64
+	if parsed.Properties.WindChill.Value != nil {
+		apparentC = parsed.Properties.WindChill.Value
+	} else if parsed.Properties.HeatIndex.Value != nil {
+		apparentC = parsed.Properties.HeatIndex.Value
+	}
+
 	obs := model.WeatherObservation{
 		StationID:   parsed.Properties.StationID,
 		StationName: parsed.Properties.StationName,
@@ -108,8 +116,7 @@ func buildObservation(parsed nwsObservationResponse) (model.WeatherObservation,
 		VisibilityMeters:     parsed.Properties.Visibility.Value,
 
 		RelativeHumidityPercent: parsed.Properties.RelativeHumidity.Value,
-		WindChillC:              parsed.Properties.WindChill.Value,
-		HeatIndexC:              parsed.Properties.HeatIndex.Value,
+		ApparentTemperatureC:    apparentC,
 
 		ElevationMeters: parsed.Properties.Elevation.Value,
 		RawMessage:      parsed.Properties.RawMessage,