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, 2 insertions, 2 deletions

diff --git a/src/client/pages/DeckDetailPage.tsx b/src/client/pages/DeckDetailPage.tsx
index d39f063..be4dc90 100644
--- a/src/client/pages/DeckDetailPage.tsx
+++ b/src/client/pages/DeckDetailPage.tsx
@@ -12,7 +12,7 @@ import { ErrorBoundary } from "../components/ErrorBoundary";
 import { LoadingSpinner } from "../components/LoadingSpinner";
 
 function DeckHeader({ deckId }: { deckId: string }) {
-	const deck = useAtomValue(deckByIdAtomFamily(deckId));
+	const { data: deck } = useAtomValue(deckByIdAtomFamily(deckId));
 
 	return (
 		<div className="mb-8">
@@ -25,7 +25,7 @@ function DeckHeader({ deckId }: { deckId: string }) {
 }
 
 function DeckStats({ deckId }: { deckId: string }) {
-	const cards = useAtomValue(cardsByDeckAtomFamily(deckId));
+	const { data: cards } = useAtomValue(cardsByDeckAtomFamily(deckId));
 
 	// Count cards due today
 	const now = new Date();