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/_isStrictComparable.js

@@ -0,0 +1,15 @@
+var isObject = require('./isObject');
+
+/**
+ * Checks if `value` is suitable for strict equality comparisons, i.e. `===`.
+ *
+ * @private
+ * @param {*} value The value to check.
+ * @returns {boolean} Returns `true` if `value` if suitable for strict
+ *  equality comparisons, else `false`.
+ */
+function isStrictComparable(value) {
+  return value === value && !isObject(value);
+}
+
+module.exports = isStrictComparable;