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/scaling.js

@@ -0,0 +1,18 @@
+/**
+ * @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 Scaling = createLucideIcon("Scaling", [
+  ["path", { d: "M21 3 9 15", key: "15kdhq" }],
+  ["path", { d: "M12 3H3v18h18v-9", key: "8suug0" }],
+  ["path", { d: "M16 3h5v5", key: "1806ms" }],
+  ["path", { d: "M14 15H9v-5", key: "pi4jk9" }]
+]);
+
+export { Scaling as default };
+//# sourceMappingURL=scaling.js.map