fix: remove 401 hard redirect, let React Query retry

The /api/me call races with TokenSync — fires before the token
provider is set. Removed the hard window.location redirect on 401
from the API client. React Query retries with backoff instead.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/src/api/hooks.ts

@@ -190,6 +190,8 @@ export function useMe() {
     queryKey: ['me'],
     queryFn: () => api.get<MeResponse>('/me'),
     staleTime: 60_000,
+    retry: 3,
+    retryDelay: 1000,
   });
 }