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/_baseKeys.js

@@ -0,0 +1,30 @@
+var isPrototype = require('./_isPrototype'),
+    nativeKeys = require('./_nativeKeys');
+
+/** Used for built-in method references. */
+var objectProto = Object.prototype;
+
+/** Used to check objects for own properties. */
+var hasOwnProperty = objectProto.hasOwnProperty;
+
+/**
+ * The base implementation of `_.keys` which doesn't treat sparse arrays as dense.
+ *
+ * @private
+ * @param {Object} object The object to query.
+ * @returns {Array} Returns the array of property names.
+ */
+function baseKeys(object) {
+  if (!isPrototype(object)) {
+    return nativeKeys(object);
+  }
+  var result = [];
+  for (var key in Object(object)) {
+    if (hasOwnProperty.call(object, key) && key != 'constructor') {
+      result.push(key);
+    }
+  }
+  return result;
+}
+
+module.exports = baseKeys;