feat(data): add React data hooks and provider with swappable resolver

[jheddings]

Summary

• Adds DataResolver interface — the abstraction seam for swapping between local dev and production Workday APIs
• Adds HttpResolver implementation that speaks the GraphQL-like protocol (find, findOne, create, update, delete) over fetch()
• Adds DataProvider React context that supplies the resolver to child hooks
• Adds useQuery<T>(model, options?) hook — returns { data, loading, error, refetch } (React Query-style)
• Adds useMutation<T>(model) hook — returns { create, update, remove, loading, error } with auto-invalidation of active queries after mutations
• All new types and functions exported from @workday/everywhere

This is Phase 2 of the data bindings feature, building on the schema types and code generation from #21. Phase 3 (local data service as Vite middleware) will make the hooks functional during everywhere view.

Test plan

• 95 tests pass across 15 test files
• just check passes (typecheck + lint)
• HttpResolver tested with mocked fetch for all CRUD operations
• useQuery/useMutation tested for correct shape and DataProvider requirement
• Integration test with real data service (Phase 3)

🤖 Generated with Claude Code