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/has-bigints/index.js

@@ -0,0 +1,11 @@
+'use strict';
+
+var $BigInt = typeof BigInt !== 'undefined' && BigInt;
+
+/** @type {import('.')} */
+module.exports = function hasNativeBigInts() {
+	return typeof $BigInt === 'function'
+		&& typeof BigInt === 'function'
+		&& typeof $BigInt(42) === 'bigint' // eslint-disable-line no-magic-numbers
+		&& typeof BigInt(42) === 'bigint'; // eslint-disable-line no-magic-numbers
+};