Convert Fetch Calls to React Query

Modernize data fetching in React using React Query with caching and retries.

category:modernization

react

react-query

data-fetching

frontend

Prompt

Convert these manual fetch calls + loading state to React Query.

Do:
- Wrap each fetch in useQuery/useMutation
- Remove duplicated loading/error state from components
- Configure sensible cache time and staleTime
- Add retry behavior only where safe

Return updated component code and suggested React Query config.