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/object-is/implementation.js

@@ -0,0 +1,19 @@
+'use strict';
+
+var numberIsNaN = function (value) {
+	return value !== value;
+};
+
+module.exports = function is(a, b) {
+	if (a === 0 && b === 0) {
+		return 1 / a === 1 / b;
+	}
+	if (a === b) {
+		return true;
+	}
+	if (numberIsNaN(a) && numberIsNaN(b)) {
+		return true;
+	}
+	return false;
+};
+