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/_createToPairs.js

@@ -0,0 +1,30 @@
+var baseToPairs = require('./_baseToPairs'),
+    getTag = require('./_getTag'),
+    mapToArray = require('./_mapToArray'),
+    setToPairs = require('./_setToPairs');
+
+/** `Object#toString` result references. */
+var mapTag = '[object Map]',
+    setTag = '[object Set]';
+
+/**
+ * Creates a `_.toPairs` or `_.toPairsIn` function.
+ *
+ * @private
+ * @param {Function} keysFunc The function to get the keys of a given object.
+ * @returns {Function} Returns the new pairs function.
+ */
+function createToPairs(keysFunc) {
+  return function(object) {
+    var tag = getTag(object);
+    if (tag == mapTag) {
+      return mapToArray(object);
+    }
+    if (tag == setTag) {
+      return setToPairs(object);
+    }
+    return baseToPairs(object, keysFunc(object));
+  };
+}
+
+module.exports = createToPairs;