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/_baseFunctions.js

@@ -0,0 +1,19 @@
+var arrayFilter = require('./_arrayFilter'),
+    isFunction = require('./isFunction');
+
+/**
+ * The base implementation of `_.functions` which creates an array of
+ * `object` function property names filtered from `props`.
+ *
+ * @private
+ * @param {Object} object The object to inspect.
+ * @param {Array} props The property names to filter.
+ * @returns {Array} Returns the function names.
+ */
+function baseFunctions(object, props) {
+  return arrayFilter(props, function(key) {
+    return isFunction(object[key]);
+  });
+}
+
+module.exports = baseFunctions;