优化

internal/biz/api.go

@@ -79,7 +79,13 @@ func (uc *APIUsecase) SyncAPIs(ctx context.Context, routes []*API) (*APISyncDiff
 	for _, item := range stored {
 		storedSet[key(item)] = item
 	}
-	diff := &APISyncDiff{Ignored: ignored}
+	// The sync API always returns JSON arrays for all three collections,
+	// including when no routes were added or removed.
+	diff := &APISyncDiff{
+		Added:   make([]*API, 0),
+		Deleted: make([]*API, 0),
+		Ignored: ignored,
+	}
 	added := make(map[string]bool)
 	for _, item := range routes {
 		routeKey := key(item)