feat(deck): add daily learning limits and today's study stats

- Add newPerDay and revPerDay fields to Deck model (Anki-style)
- Add settings modal to configure daily limits per deck
- Display today's studied counts (new/review/learning) on deck page
- Add i18n translations for all 8 languages
- Fix JSON syntax errors in fr-FR.json and it-IT.json
- Fix double counting bug in repoGetTodayStudyStats

messages/zh-CN.json

@@ -103,6 +103,18 @@
     "resetSuccess": "成功重置 {count} 张卡片",
     "resetting": "重置中...",
     "cancel": "取消",
+    "settings": "设置",
+    "settingsTitle": "牌组设置",
+    "newPerDay": "每日新卡数量",
+    "newPerDayHint": "每天最多学习的新卡片数量",
+    "revPerDay": "每日复习数量",
+    "revPerDayHint": "每天最多复习的卡片数量",
+    "save": "保存",
+    "saving": "保存中...",
+    "settingsSaved": "设置已保存",
+    "todayNew": "新卡",
+    "todayReview": "复习",
+    "todayLearning": "学习中",
     "error": {
       "update": "您没有权限更新此卡片",
       "delete": "您没有权限删除此卡片",