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/_basePullAt.js

@@ -0,0 +1,37 @@
+var baseUnset = require('./_baseUnset'),
+    isIndex = require('./_isIndex');
+
+/** Used for built-in method references. */
+var arrayProto = Array.prototype;
+
+/** Built-in value references. */
+var splice = arrayProto.splice;
+
+/**
+ * The base implementation of `_.pullAt` without support for individual
+ * indexes or capturing the removed elements.
+ *
+ * @private
+ * @param {Array} array The array to modify.
+ * @param {number[]} indexes The indexes of elements to remove.
+ * @returns {Array} Returns `array`.
+ */
+function basePullAt(array, indexes) {
+  var length = array ? indexes.length : 0,
+      lastIndex = length - 1;
+
+  while (length--) {
+    var index = indexes[length];
+    if (length == lastIndex || index !== previous) {
+      var previous = index;
+      if (isIndex(index)) {
+        splice.call(array, index, 1);
+      } else {
+        baseUnset(array, index);
+      }
+    }
+  }
+  return array;
+}
+
+module.exports = basePullAt;