Documented the two different date and time decoding behaviours that could be found at the OpenAPI specification in the library target.

Sources/AmiiboService/openapi.yaml

@@ -418,7 +418,10 @@ components:
         - gameID
         - gameName
     AmiiboRelease:
-      description: A type that contains the regional release dates of an amiibo.
+      description: |
+        A type that contains the regional release dates of an amiibo.
+
+        Note: The service returns these dates as date-only strings (`yyyy-MM-dd`) without a time component, even though the properties declare the `date-time` format. The `date-time` format is kept deliberately so the generated code produces `Date` values, and the date-only strings are decoded by the custom transcoder configured in the live client, which interprets them as midnight UTC.
       type: object
       properties:
         au:
@@ -511,7 +514,10 @@ components:
         - key
         - name
     LastUpdated:
-      description: A type that contains the date and time when the service data was last updated.
+      description: |
+        A type that contains the date and time when the service data was last updated.
+
+        Note: The service returns this timestamp in the `yyyy-MM-dd'T'HH:mm:ss.SSSSSS` format without a timezone offset, so it is not a strictly valid RFC 3339 `date-time` value. The `date-time` format is kept deliberately so the generated code produces a `Date` value, and the timestamp is decoded by the custom transcoder configured in the live client, which interprets it as UTC.
       type: object
       properties:
         lastUpdated: