Added source and user marks to opportunities type. Any ignored errors are deferred to //nolint with a comment instead of being silently dropped

internal/mock/findATender/handler.go

@@ -65,7 +65,8 @@ func decodeCursor(c string) (int, error) {
 func badRequest(w http.ResponseWriter, msg string) {
 	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(http.StatusBadRequest)
-	_ = json.NewEncoder(w).Encode(map[string]string{"error": msg}) // the client has gone
+	body := map[string]string{"error": msg}
+	json.NewEncoder(w).Encode(body) //nolint:errcheck,gosec // the client may have gone; nothing to do
 }
 
 // parseTime reads a query timestamp. Values without an offset (the documented