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/_castRest.js

@@ -0,0 +1,14 @@
+var baseRest = require('./_baseRest');
+
+/**
+ * A `baseRest` alias which can be replaced with `identity` by module
+ * replacement plugins.
+ *
+ * @private
+ * @type {Function}
+ * @param {Function} func The function to apply a rest parameter to.
+ * @returns {Function} Returns the new function.
+ */
+var castRest = baseRest;
+
+module.exports = castRest;