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/arg/package.json

@@ -0,0 +1,28 @@
+{
+  "name": "arg",
+  "version": "5.0.2",
+  "description": "Unopinionated, no-frills CLI argument parser",
+  "main": "index.js",
+  "types": "index.d.ts",
+  "repository": "vercel/arg",
+  "author": "Josh Junon <junon@wavetilt.com>",
+  "license": "MIT",
+  "files": [
+    "index.js",
+    "index.d.ts"
+  ],
+  "scripts": {
+    "test": "WARN_EXIT=1 jest --coverage -w 2"
+  },
+  "devDependencies": {
+    "chai": "^4.1.1",
+    "jest": "^27.0.6",
+    "prettier": "^2.3.2"
+  },
+  "prettier": {
+    "arrowParens": "always",
+    "singleQuote": true,
+    "tabWidth": 2,
+    "trailingComma": "none"
+  }
+}