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/regeneratorKeys.js

@@ -0,0 +1,10 @@
+function _regeneratorKeys(e) {
+  var n = Object(e),
+    r = [];
+  for (var t in n) r.unshift(t);
+  return function e() {
+    for (; r.length;) if ((t = r.pop()) in n) return e.value = t, e.done = !1, e;
+    return e.done = !0, e;
+  };
+}
+module.exports = _regeneratorKeys, module.exports.__esModule = true, module.exports["default"] = module.exports;