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/_arraySample.js

@@ -0,0 +1,15 @@
+var baseRandom = require('./_baseRandom');
+
+/**
+ * A specialized version of `_.sample` for arrays.
+ *
+ * @private
+ * @param {Array} array The array to sample.
+ * @returns {*} Returns the random element.
+ */
+function arraySample(array) {
+  var length = array.length;
+  return length ? array[baseRandom(0, length - 1)] : undefined;
+}
+
+module.exports = arraySample;