State Management

This is a solid reference for combining TanStack Query v5 with Zustand v5 in React apps, covering 26+ patterns from basic data fetching to optimistic updates. The breaking changes section up front is helpful since v5 changed `cacheTime` to `gcTime` and removed `onSuccess` from `useQuery`. I like the query keys factory pattern and the clear separation between server state (React Query) and client state (Zustand). The optimistic update examples with rollback logic are thorough. Most useful when you're setting up data fetching infrastructure or need to sync server cache with local stores. The security note about not persisting auth tokens in localStorage is worth highlighting to your team.