Add altStyleId to PetAppearance type and resolvers

src/server/types/Pet.js

@@ -33,6 +33,9 @@ const resolvers = {
         return null;
       }
 
+      // Neopets may omit this field entirely; treat "missing" as null.
+      const altStyleId = customPetData.custom_pet.alt_style ?? null;
+
       const petType = await petTypeBySpeciesAndColorLoader.load({
         speciesId: customPetData.custom_pet.species_id,
         colorId: customPetData.custom_pet.color_id,
@@ -53,7 +56,7 @@ const resolvers = {
         .join(",");
       petState = petStates.find((ps) => ps.swfAssetIds === swfAssetIdsString);
       if (petState) {
-        return { id: petState.id };
+        return { id: petState.id, altStyleId };
       }
 
       // Next, look for a pet state matching the same pose. (This can happen if
@@ -71,7 +74,7 @@ const resolvers = {
               `because it matches pose ${pose}. Actual pet state for these ` +
               `assets not found: ${swfAssetIdsString}`,
           );
-          return { id: petState.id };
+          return { id: petState.id, altStyleId };
         }
       }
 
@@ -85,7 +88,7 @@ const resolvers = {
             `as an UNKNOWN fallback pose. Actual pet state for these ` +
             `assets not found: ${swfAssetIdsString}`,
         );
-        return { id: petState.id };
+        return { id: petState.id, altStyleId };
       }
 
       // If we still don't have a pet state, raise an error. (This can happen

src/server/types/PetAppearance.js

@@ -78,6 +78,12 @@ const typeDefs = gql`
     """
     id: ID!
 
+    """
+    The ID of the alt style used to render this appearance, if any.
+    Null when this appearance is not using an alt style.
+    """
+    altStyleId: ID
+
     species: Species!
     color: Color!
     pose: Pose!