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/_baseIsMap.js

@@ -0,0 +1,18 @@
+var getTag = require('./_getTag'),
+    isObjectLike = require('./isObjectLike');
+
+/** `Object#toString` result references. */
+var mapTag = '[object Map]';
+
+/**
+ * The base implementation of `_.isMap` without Node.js optimizations.
+ *
+ * @private
+ * @param {*} value The value to check.
+ * @returns {boolean} Returns `true` if `value` is a map, else `false`.
+ */
+function baseIsMap(value) {
+  return isObjectLike(value) && getTag(value) == mapTag;
+}
+
+module.exports = baseIsMap;