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/split.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 Split = createLucideIcon("Split", [
+  ["path", { d: "M16 3h5v5", key: "1806ms" }],
+  ["path", { d: "M8 3H3v5", key: "15dfkv" }],
+  ["path", { d: "M12 22v-8.3a4 4 0 0 0-1.172-2.872L3 3", key: "1qrqzj" }],
+  ["path", { d: "m15 9 6-6", key: "ko1vev" }]
+]);
+
+export { Split as default };
+//# sourceMappingURL=split.js.map