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/css-tree/cjs/utils/index.cjs

@@ -0,0 +1,20 @@
+'use strict';
+
+const clone = require('./clone.cjs');
+const ident = require('./ident.cjs');
+const List = require('./List.cjs');
+const names = require('./names.cjs');
+const string = require('./string.cjs');
+const url = require('./url.cjs');
+
+
+
+exports.clone = clone.clone;
+exports.ident = ident;
+exports.List = List.List;
+exports.isCustomProperty = names.isCustomProperty;
+exports.keyword = names.keyword;
+exports.property = names.property;
+exports.vendorPrefix = names.vendorPrefix;
+exports.string = string;
+exports.url = url;