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/@nodelib/fs.stat/out/adapters/fs.d.ts

@@ -0,0 +1,13 @@
+/// <reference types="node" />
+import * as fs from 'fs';
+import type { ErrnoException } from '../types';
+export declare type StatAsynchronousMethod = (path: string, callback: (error: ErrnoException | null, stats: fs.Stats) => void) => void;
+export declare type StatSynchronousMethod = (path: string) => fs.Stats;
+export interface FileSystemAdapter {
+    lstat: StatAsynchronousMethod;
+    stat: StatAsynchronousMethod;
+    lstatSync: StatSynchronousMethod;
+    statSync: StatSynchronousMethod;
+}
+export declare const FILE_SYSTEM_ADAPTER: FileSystemAdapter;
+export declare function createFileSystemAdapter(fsMethods?: Partial<FileSystemAdapter>): FileSystemAdapter;