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/_createRelationalOperation.js

@@ -0,0 +1,20 @@
+var toNumber = require('./toNumber');
+
+/**
+ * Creates a function that performs a relational operation on two values.
+ *
+ * @private
+ * @param {Function} operator The function to perform the operation.
+ * @returns {Function} Returns the new relational operation function.
+ */
+function createRelationalOperation(operator) {
+  return function(value, other) {
+    if (!(typeof value == 'string' && typeof other == 'string')) {
+      value = toNumber(value);
+      other = toNumber(other);
+    }
+    return operator(value, other);
+  };
+}
+
+module.exports = createRelationalOperation;