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/isArrayLike.js

@@ -0,0 +1,33 @@
+var isFunction = require('./isFunction'),
+    isLength = require('./isLength');
+
+/**
+ * Checks if `value` is array-like. A value is considered array-like if it's
+ * not a function and has a `value.length` that's an integer greater than or
+ * equal to `0` and less than or equal to `Number.MAX_SAFE_INTEGER`.
+ *
+ * @static
+ * @memberOf _
+ * @since 4.0.0
+ * @category Lang
+ * @param {*} value The value to check.
+ * @returns {boolean} Returns `true` if `value` is array-like, else `false`.
+ * @example
+ *
+ * _.isArrayLike([1, 2, 3]);
+ * // => true
+ *
+ * _.isArrayLike(document.body.children);
+ * // => true
+ *
+ * _.isArrayLike('abc');
+ * // => true
+ *
+ * _.isArrayLike(_.noop);
+ * // => false
+ */
+function isArrayLike(value) {
+  return value != null && isLength(value.length) && !isFunction(value);
+}
+
+module.exports = isArrayLike;