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/_baseHasIn.js

@@ -0,0 +1,13 @@
+/**
+ * The base implementation of `_.hasIn` without support for deep paths.
+ *
+ * @private
+ * @param {Object} [object] The object to query.
+ * @param {Array|string} key The key to check.
+ * @returns {boolean} Returns `true` if `key` exists, else `false`.
+ */
+function baseHasIn(object, key) {
+  return object != null && key in Object(object);
+}
+
+module.exports = baseHasIn;