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/file-x-2.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 FileX2 = createLucideIcon("FileX2", [
+  ["path", { d: "M4 22h14a2 2 0 0 0 2-2V7.5L14.5 2H6a2 2 0 0 0-2 2v4", key: "702lig" }],
+  ["path", { d: "M14 2v6h6", key: "1kof46" }],
+  ["path", { d: "m3 12.5 5 5", key: "1qls4r" }],
+  ["path", { d: "m8 12.5-5 5", key: "b853mi" }]
+]);
+
+export { FileX2 as default };
+//# sourceMappingURL=file-x-2.js.map