feat: 学習カード数の上限を撤廃

REVIEW_CARDS_LIMIT（復習カード80枚制限）とnewCardsPerDay（1日の新規カード制限）
を削除し、期日が来たすべてのカードを制限なく返すように変更。

削除した主な要素:
- REVIEW_CARDS_LIMIT定数とカード取得時のlimitパラメータ
- newCardsPerDayフィールド（DB schema, 型定義, Zod schema, sync, CRDT）
- countDueNewCards, countDueReviewCards, findDueNewCardsForStudy,
  findDueReviewCardsForStudy（CardRepository）
- countTodayNewCardReviews（ReviewLogRepository）
- デッキルートからのReviewLogRepository依存

https://claude.ai/code/session_018hrEJ9vg3RPoeAPyEc17gS

1 files changed, 2 insertions, 13 deletions

diff --git a/src/server/routes/study.ts b/src/server/routes/study.ts
index d05f3ca..0f42f93 100644
--- a/src/server/routes/study.ts
+++ b/src/server/routes/study.ts
@@ -52,20 +52,9 @@ export function createStudyRouter(deps: StudyDependencies) {
 
 			const now = new Date();
 
-			// Calculate new card budget based on today's already-reviewed new cards
-			const reviewedNewCards = await reviewLogRepo.countTodayNewCardReviews(
-				deckId,
-				now,
-			);
-			const newCardBudget = Math.max(0, deck.newCardsPerDay - reviewedNewCards);
+			const cards = await cardRepo.findDueCardsForStudy(deckId, now);
 
-			// Fetch new cards (limited) and review cards separately
-			const [newCards, reviewCards] = await Promise.all([
-				cardRepo.findDueNewCardsForStudy(deckId, now, newCardBudget),
-				cardRepo.findDueReviewCardsForStudy(deckId, now, 80),
-			]);
-
-			return c.json({ cards: [...newCards, ...reviewCards] }, 200);
+			return c.json({ cards }, 200);
 		})
 		.post(
 			"/:cardId",