feat(frontend): add API client, layout, and routing

- Create Axios-based API client with sources, jobs, and dashboard endpoints
- Add responsive Layout component with navigation sidebar
- Set up React Router with Dashboard, Backups, and Settings routes
- Configure TanStack Query provider with default options
- Use lucide-react for navigation icons

frontend/node_modules/lodash/now.js

@@ -0,0 +1,23 @@
+var root = require('./_root');
+
+/**
+ * Gets the timestamp of the number of milliseconds that have elapsed since
+ * the Unix epoch (1 January 1970 00:00:00 UTC).
+ *
+ * @static
+ * @memberOf _
+ * @since 2.4.0
+ * @category Date
+ * @returns {number} Returns the timestamp.
+ * @example
+ *
+ * _.defer(function(stamp) {
+ *   console.log(_.now() - stamp);
+ * }, _.now());
+ * // => Logs the number of milliseconds it took for the deferred invocation.
+ */
+var now = function() {
+  return root.Date.now();
+};
+
+module.exports = now;