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/_arrayShuffle.js

@@ -0,0 +1,15 @@
+var copyArray = require('./_copyArray'),
+    shuffleSelf = require('./_shuffleSelf');
+
+/**
+ * A specialized version of `_.shuffle` for arrays.
+ *
+ * @private
+ * @param {Array} array The array to shuffle.
+ * @returns {Array} Returns the new shuffled array.
+ */
+function arrayShuffle(array) {
+  return shuffleSelf(copyArray(array));
+}
+
+module.exports = arrayShuffle;