openweather: refactored the OpenWeather source files to relocate normalization logic to internal/normalizers.

internal/normalizers/openweather/register.go

@@ -1,3 +1,4 @@
+// FILE: ./internal/normalizers/openweather/register.go
 package openweather
 
 import (
@@ -5,15 +6,11 @@ import (
 )
 
 // Register registers OpenWeather normalizers into the provided registry.
-//
-// This is intentionally empty as a stub. As normalizers are implemented,
-// register them here, e.g.:
-//
-//	reg.Register(ObservationNormalizer{})
 func Register(reg *fknormalize.Registry) {
 	if reg == nil {
 		return
 	}
 
-	// TODO: register OpenWeather normalizers here.
+	// Observations
+	reg.Register(ObservationNormalizer{})
 }