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/_arraySampleSize.js

@@ -0,0 +1,17 @@
+var baseClamp = require('./_baseClamp'),
+    copyArray = require('./_copyArray'),
+    shuffleSelf = require('./_shuffleSelf');
+
+/**
+ * A specialized version of `_.sampleSize` for arrays.
+ *
+ * @private
+ * @param {Array} array The array to sample.
+ * @param {number} n The number of elements to sample.
+ * @returns {Array} Returns the random elements.
+ */
+function arraySampleSize(array, n) {
+  return shuffleSelf(copyArray(array), baseClamp(n, 0, array.length));
+}
+
+module.exports = arraySampleSize;