新增奖励兑换模式与奖励设置，并持久化兑换记录

src/i18n/locales/en-US.json

@@ -310,6 +310,8 @@
     "settlements": "Settlements",
     "reasons": "Reasons",
     "autoScore": "Auto Score",
+    "rewardExchange": "Reward Exchange",
+    "rewardSettings": "Reward Settings",
     "settings": "Settings",
     "remoteDb": "Remote Database",
     "refreshStatus": "Refresh Status",
@@ -516,6 +518,46 @@
     "deleteFailed": "Delete failed",
     "others": "Others"
   },
+  "rewardExchange": {
+    "title": "Reward Exchange",
+    "enterMode": "Enter Exchange Mode",
+    "exitMode": "Exit Exchange Mode",
+    "modeHint": "Reward exchange mode is active. Click a student card to choose an available reward.",
+    "normalHint": "Current cards show original score. Enter mode to display redeemable reward points.",
+    "remainingRewardPoints": "Remaining Reward Points",
+    "currentScore": "Current Score",
+    "chooseRewardTitle": "Choose Reward for {{name}}",
+    "currentRewardPoints": "Current reward points: {{points}}",
+    "costLabel": "Cost points: {{points}}",
+    "redeemNow": "Redeem",
+    "noAffordableRewards": "No rewards can be redeemed now. Earn more points first.",
+    "redeemSuccess": "{{student}} redeemed \"{{reward}}\" and spent {{points}} points",
+    "redeemFailed": "Redeem failed",
+    "recordsTitle": "Redemption Records",
+    "recordStudent": "Student",
+    "recordReward": "Reward",
+    "recordCost": "Cost",
+    "recordTime": "Redeemed At"
+  },
+  "rewardSettings": {
+    "title": "Reward Settings",
+    "addReward": "Add Reward",
+    "addTitle": "Add Reward",
+    "editTitle": "Edit Reward",
+    "rewardName": "Reward Name",
+    "costPoints": "Cost Points",
+    "namePlaceholder": "e.g. Homework-Free Card",
+    "costPlaceholder": "Enter cost points",
+    "nameRequired": "Please enter reward name",
+    "costRequired": "Please enter positive integer points",
+    "createSuccess": "Reward created",
+    "createFailed": "Create reward failed",
+    "updateSuccess": "Reward updated",
+    "updateFailed": "Update reward failed",
+    "deleteSuccess": "Reward deleted",
+    "deleteFailed": "Delete reward failed",
+    "deleteConfirm": "Delete reward \"{{name}}\"?"
+  },
   "leaderboard": {
     "title": "Points Leaderboard",
     "rank": "Rank",