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/en-US.json

@@ -103,6 +103,18 @@
     "resetSuccess": "Successfully reset {count} cards",
     "resetting": "Resetting...",
     "cancel": "Cancel",
+    "settings": "Settings",
+    "settingsTitle": "Deck Settings",
+    "newPerDay": "New Cards Per Day",
+    "newPerDayHint": "Maximum new cards to learn each day",
+    "revPerDay": "Review Cards Per Day",
+    "revPerDayHint": "Maximum review cards each day",
+    "save": "Save",
+    "saving": "Saving...",
+    "settingsSaved": "Settings saved",
+    "todayNew": "New",
+    "todayReview": "Review",
+    "todayLearning": "Learning",
     "error": {
       "update": "You do not have permission to update this card.",
       "delete": "You do not have permission to delete this card.",