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/lucide-react/dist/esm/icons/shield-off.js

@@ -0,0 +1,17 @@
+/**
+ * @license lucide-react v0.303.0 - ISC
+ *
+ * This source code is licensed under the ISC license.
+ * See the LICENSE file in the root directory of this source tree.
+ */
+
+import createLucideIcon from '../createLucideIcon.js';
+
+const ShieldOff = createLucideIcon("ShieldOff", [
+  ["path", { d: "M19.7 14a6.9 6.9 0 0 0 .3-2V5l-8-3-3.2 1.2", key: "342pvf" }],
+  ["path", { d: "m2 2 20 20", key: "1ooewy" }],
+  ["path", { d: "M4.7 4.7 4 5v7c0 6 8 10 8 10a20.3 20.3 0 0 0 5.62-4.38", key: "p0ycf4" }]
+]);
+
+export { ShieldOff as default };
+//# sourceMappingURL=shield-off.js.map