add ultraviolet support (bare-client-custom)

client/sw.js

@@ -0,0 +1,14 @@
+/*global UVServiceWorker,__uv$config*/
+/*
+ * Stock service worker script.
+ * Users can provide their own sw.js if they need to extend the functionality of the service worker.
+ * Ideally, this will be registered under the scope in uv.config.js so it will not need to be modified.
+ * However, if a user changes the location of uv.bundle.js/uv.config.js or sw.js is not relative to them, they will need to modify this script locally.
+ */
+importScripts('uv/uv.bundle.js');
+importScripts('uv.config.js');
+importScripts(__uv$config.sw || 'uv.sw.js');
+
+const sw = new UVServiceWorker();
+
+self.addEventListener('fetch', (event) => event.respondWith(sw.fetch(event)));