perf: add select clause to admin review query, exclude large TEXT columns

- Only fetch display-needed columns, skip backText TEXT column
- Reduces data transfer and query time significantly

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/modules/review/admin-review.controller.ts

@@ -31,12 +31,15 @@ export class AdminReviewController {
       where.frontText = { contains: search };
     }
 
+    const select = {
+      id: true, userId: true, frontText: true, difficulty: true,
+      status: true, scheduleState: true, intervalDays: true,
+      repetitionCount: true, lapseCount: true, nextReviewAt: true,
+    };
+
     const [items, total] = await Promise.all([
       this.prisma.reviewCard.findMany({
-        where,
-        orderBy: { createdAt: 'desc' },
-        take,
-        skip,
+        where, orderBy: { createdAt: 'desc' }, take, skip, select,
       }),
       this.prisma.reviewCard.count({ where }),
     ]);