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/lib/syntax/config/parser-selector.js

@@ -0,0 +1,15 @@
+import { Selector } from '../scope/index.js';
+import pseudo from '../pseudo/index.js';
+import * as node from '../node/index-parse-selector.js';
+
+export default {
+    parseContext: {
+        default: 'SelectorList',
+        selectorList: 'SelectorList',
+        selector: 'Selector'
+    },
+    scope: { Selector },
+    atrule: {},
+    pseudo,
+    node
+};