This commit combines multiple improvements to the React Query migration:

Performance Optimization:
- Increase default staleTime from 10s to 30s for better performance
- Reduces unnecessary network requests while maintaining data freshness

Error Handling:
- Add ErrorBoundary component with user-friendly error UI
- Integrated at app root level for comprehensive coverage
- Provides error details and reload option

Documentation:
- Add docs/auth-architecture.md explaining AuthContext design decisions
- Document why AuthContext is preferred over React Query for current user

Code Cleanup:
- Remove all JSDoc comments from hooks and components
- Keep essential inline comments for clarity
- Simplifies code readability

Files modified:
- src/lib/query-client.ts - Optimized staleTime
- src/main.tsx - Added ErrorBoundary wrapper
- src/components/ErrorBoundary.tsx - New component
- src/hooks/useMemoQueries.ts - Removed JSDoc
- src/hooks/useUserQueries.ts - Removed JSDoc
- src/components/PagedMemoList/PagedMemoList.tsx - Removed JSDoc
- docs/auth-architecture.md - New documentation

All changes verified with TypeScript compilation and production build.

🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>