@tanstack/react-query's entrypoint imports react at module load time
(useQueries.js) regardless of whether a hook is ever called — so
marking react optional was actively broken: any consumer without
react installed would fail on the bare import of queryOptions.
Workspace tests never caught this because react is hoisted from
other apps/* packages in this monorepo. Caught via a genuine install
test in the new a2aq-tanstack repo, where no such hoisting exists.