feat: 포인트 적립내역 조회 — GET /auth/point-history

- point_history 최신순 조회(최대 100건), PointHistoryResponse
- PointService.getHistory, 인터셉터 경로 등록

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/main/java/com/sb/web/point/PointService.java

@@ -38,4 +38,9 @@ public class PointService {
         Long p = pointMapper.getPoints(memberId);
         return p == null ? 0L : p;
     }
+
+    /** 최근 포인트 적립/차감 내역 (최신순) */
+    public java.util.List<PointHistoryResponse> getHistory(Long memberId) {
+        return pointMapper.findHistory(memberId, 100);
+    }
 }