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/functionsIn.js

@@ -0,0 +1,31 @@
+var baseFunctions = require('./_baseFunctions'),
+    keysIn = require('./keysIn');
+
+/**
+ * Creates an array of function property names from own and inherited
+ * enumerable properties of `object`.
+ *
+ * @static
+ * @memberOf _
+ * @since 4.0.0
+ * @category Object
+ * @param {Object} object The object to inspect.
+ * @returns {Array} Returns the function names.
+ * @see _.functions
+ * @example
+ *
+ * function Foo() {
+ *   this.a = _.constant('a');
+ *   this.b = _.constant('b');
+ * }
+ *
+ * Foo.prototype.c = _.constant('c');
+ *
+ * _.functionsIn(new Foo);
+ * // => ['a', 'b', 'c']
+ */
+function functionsIn(object) {
+  return object == null ? [] : baseFunctions(object, keysIn(object));
+}
+
+module.exports = functionsIn;