feat: implement AI usage tracking and quota management with daily usage records

frontend/src/components/MyResults.tsx

@@ -158,7 +158,7 @@ export default function MyResults({ onLoadExam }: Props) {
                     {retakingId === r.id ? t('common.loading') : t('results.retakeExam')}
                   </button>
                   <button className="btn btn-sm" onClick={() => void reviewResult(r)}>
-                    {t('common.edit')}
+                    {t('results.review')}
                   </button>
                   {deleteConfirm === r.id ? (
                     <div className="workspace-delete-confirm">

frontend/src/components/Overview.tsx

@@ -29,7 +29,7 @@ export default function Overview({ examCount, resultCount, recentResults, onLoad
   useEffect(() => {
     resultApi.getScoreTrends()
       .then((data) => setTrends(data))
-      .catch(() => {/* ignore */})
+      .catch(() => {/* ignore */ })
       .finally(() => setTrendsLoading(false))
   }, [])