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/fastq/example.js

@@ -0,0 +1,14 @@
+'use strict'
+
+/* eslint-disable no-var */
+
+var queue = require('./')(worker, 1)
+
+queue.push(42, function (err, result) {
+  if (err) { throw err }
+  console.log('the result is', result)
+})
+
+function worker (arg, cb) {
+  cb(null, 42 * 2)
+}