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/pretty-format/build/plugins/lib/markup.d.ts

@@ -0,0 +1,13 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+import type { Config, Printer, Refs } from '../../types';
+export declare const printProps: (keys: Array<string>, props: Record<string, unknown>, config: Config, indentation: string, depth: number, refs: Refs, printer: Printer) => string;
+export declare const printChildren: (children: Array<unknown>, config: Config, indentation: string, depth: number, refs: Refs, printer: Printer) => string;
+export declare const printText: (text: string, config: Config) => string;
+export declare const printComment: (comment: string, config: Config) => string;
+export declare const printElement: (type: string, printedProps: string, printedChildren: string, config: Config, indentation: string) => string;
+export declare const printElementAsLeaf: (type: string, config: Config) => string;