React Native Data Fetching with TanStack Query

Instructions

All server state flows through @tanstack/react-query v5. Components never call fetch directly -- they call a typed hook that wraps useQuery / useMutation.

1. Client Setup

// src/app/queryClient.ts
import { QueryClient, focusManager } from '@tanstack/react-query';
import { AppState } from 'react-native';
import type { AppStateStatus } from 'react-native';