Add server-generated /config.js; add error boundary

web/src/components/routes.js

@@ -0,0 +1,16 @@
+import config from "../app/config";
+import {shortUrl} from "../app/utils";
+
+const routes = {
+    root: config.appRoot,
+    settings: "/settings",
+    subscription: "/:topic",
+    subscriptionExternal: "/:baseUrl/:topic",
+    forSubscription: (subscription) => {
+        if (subscription.baseUrl !== window.location.origin) {
+            return `/${shortUrl(subscription.baseUrl)}/${subscription.topic}`;
+        }
+        return `/${subscription.topic}`;
+    }
+};
+export default routes;