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/dom-accessibility-api/dist/accessible-name.d.ts

@@ -0,0 +1,9 @@
+import { ComputeTextAlternativeOptions } from "./accessible-name-and-description";
+/**
+ * implements https://w3c.github.io/accname/#mapping_additional_nd_name
+ * @param root
+ * @param options
+ * @returns
+ */
+export declare function computeAccessibleName(root: Element, options?: ComputeTextAlternativeOptions): string;
+//# sourceMappingURL=accessible-name.d.ts.map