refactor(atoms): migrate to jotai-tanstack-query from custom reloadable atoms

Replace custom createReloadableAtom/createReloadableAtomFamily with
atomWithSuspenseQuery from jotai-tanstack-query, leveraging TanStack
Query's built-in caching, invalidation, and Suspense support.

- Add @tanstack/query-core and jotai-tanstack-query dependencies
- Create shared QueryClient instance (src/client/queryClient.ts)
- Migrate all data atoms (decks, cards, study, noteTypes) to atomWithSuspenseQuery
- Update page components to use .data destructuring and queryClient.invalidateQueries()
- Update all test files to use QueryClient for data hydration
- Remove src/client/atoms/utils.ts (no longer needed)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/src/client/pages/StudyPage.tsx b/src/client/pages/StudyPage.tsx
index cec11d3..dd82b27 100644
--- a/src/client/pages/StudyPage.tsx
+++ b/src/client/pages/StudyPage.tsx
@@ -37,7 +37,9 @@ const RatingStyles: Record<Rating, string> = {
 };
 
 function StudySession({ deckId }: { deckId: string }) {
-	const { deck, cards } = useAtomValue(studyDataAtomFamily(deckId));
+	const {
+		data: { deck, cards },
+	} = useAtomValue(studyDataAtomFamily(deckId));
 
 	// Session state (kept as useState - transient UI state)
 	const [currentIndex, setCurrentIndex] = useState(0);