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/object-inspect/test/circular.js

@@ -0,0 +1,16 @@
+var inspect = require('../');
+var test = require('tape');
+
+test('circular', function (t) {
+    t.plan(2);
+    var obj = { a: 1, b: [3, 4] };
+    obj.c = obj;
+    t.equal(inspect(obj), '{ a: 1, b: [ 3, 4 ], c: [Circular] }');
+
+    var double = {};
+    double.a = [double];
+    double.b = {};
+    double.b.inner = double.b;
+    double.b.obj = double;
+    t.equal(inspect(double), '{ a: [ [Circular] ], b: { inner: [Circular], obj: [Circular] } }');
+});