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/@babel/runtime/helpers/esm/slicedToArray.js

@@ -0,0 +1,8 @@
+import arrayWithHoles from "./arrayWithHoles.js";
+import iterableToArrayLimit from "./iterableToArrayLimit.js";
+import unsupportedIterableToArray from "./unsupportedIterableToArray.js";
+import nonIterableRest from "./nonIterableRest.js";
+function _slicedToArray(r, e) {
+  return arrayWithHoles(r) || iterableToArrayLimit(r, e) || unsupportedIterableToArray(r, e) || nonIterableRest();
+}
+export { _slicedToArray as default };