fix(deck): change review card limit to 80 and simplify deck detail stats

Review card limit is reduced from 100 to 80 across deck list, deck detail,
and study routes. Deck detail page now shows only total card count and due
card count (with budget limits applied), matching the deck list and study
screen numbers.

https://claude.ai/code/session_01NAj4waQhwSSXV9EbgioX2j

3 files changed, 18 insertions, 4 deletions

diff --git a/src/server/routes/decks.ts b/src/server/routes/decks.ts
index 6a24c66..d73aa0c 100644
--- a/src/server/routes/decks.ts
+++ b/src/server/routes/decks.ts
@@ -22,7 +22,7 @@ const deckIdParamSchema = z.object({
 	id: z.uuid(),
 });
 
-const REVIEW_CARDS_LIMIT = 100;
+const REVIEW_CARDS_LIMIT = 80;
 
 export function createDecksRouter(deps: DeckDependencies) {
 	const { deckRepo, cardRepo, reviewLogRepo } = deps;
@@ -82,7 +82,21 @@ export function createDecksRouter(deps: DeckDependencies) {
 				throw Errors.notFound("Deck not found", "DECK_NOT_FOUND");
 			}
 
-			return c.json({ deck }, 200);
+			const now = new Date();
+			const [dueNewCards, dueReviewCards, reviewedNewCards] = await Promise.all(
+				[
+					cardRepo.countDueNewCards(deck.id, now),
+					cardRepo.countDueReviewCards(deck.id, now),
+					reviewLogRepo.countTodayNewCardReviews(deck.id, now),
+				],
+			);
+
+			const newCardBudget = Math.max(0, deck.newCardsPerDay - reviewedNewCards);
+			const newCardsToStudy = Math.min(dueNewCards, newCardBudget);
+			const reviewCardsToStudy = Math.min(dueReviewCards, REVIEW_CARDS_LIMIT);
+			const dueCardCount = newCardsToStudy + reviewCardsToStudy;
+
+			return c.json({ deck: { ...deck, dueCardCount } }, 200);
 		})
 		.put(
 			"/:id",
diff --git a/src/server/routes/study.test.ts b/src/server/routes/study.test.ts
index a58ea0d..514d966 100644
--- a/src/server/routes/study.test.ts
+++ b/src/server/routes/study.test.ts
@@ -198,7 +198,7 @@ describe("GET /api/decks/:deckId/study", () => {
 		expect(mockCardRepo.findDueReviewCardsForStudy).toHaveBeenCalledWith(
 			DECK_ID,
 			expect.any(Date),
-			100,
+			80,
 		);
 	});
 
diff --git a/src/server/routes/study.ts b/src/server/routes/study.ts
index efd450c..d05f3ca 100644
--- a/src/server/routes/study.ts
+++ b/src/server/routes/study.ts
@@ -62,7 +62,7 @@ export function createStudyRouter(deps: StudyDependencies) {
 			// Fetch new cards (limited) and review cards separately
 			const [newCards, reviewCards] = await Promise.all([
 				cardRepo.findDueNewCardsForStudy(deckId, now, newCardBudget),
-				cardRepo.findDueReviewCardsForStudy(deckId, now, 100),
+				cardRepo.findDueReviewCardsForStudy(deckId, now, 80),
 			]);
 
 			return c.json({ cards: [...newCards, ...reviewCards] }, 200);