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/chai/index.mjs

@@ -0,0 +1,14 @@
+import chai from './index.js';
+
+export const expect = chai.expect;
+export const version = chai.version;
+export const Assertion = chai.Assertion;
+export const AssertionError = chai.AssertionError;
+export const util = chai.util;
+export const config = chai.config;
+export const use = chai.use;
+export const should = chai.should;
+export const assert = chai.assert;
+export const core = chai.core;
+
+export default chai;