feat: [loan] 상품권 summary에 접대비 해당 집계 추가

- expense_accounts 테이블에서 접대비(상품권) 건수/금액 조회
- entertainment_count, entertainment_amount 응답 필드 추가

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/Services/LoanService.php

@@ -152,6 +152,17 @@ public function summary(?int $userId = null, ?string $category = null): array
             $result['used_count'] = (int) $stats->used_count;
             $result['used_amount'] = (float) $stats->used_amount;
             $result['disposed_count'] = (int) $stats->disposed_count;
+
+            // 접대비 해당 집계 (expense_accounts 테이블에서 조회)
+            $entertainmentStats = ExpenseAccount::query()
+                ->where('tenant_id', $tenantId)
+                ->where('account_type', ExpenseAccount::TYPE_ENTERTAINMENT)
+                ->where('sub_type', ExpenseAccount::SUB_TYPE_GIFT_CERTIFICATE)
+                ->selectRaw('COUNT(*) as count, COALESCE(SUM(amount), 0) as amount')
+                ->first();
+
+            $result['entertainment_count'] = (int) ($entertainmentStats->count ?? 0);
+            $result['entertainment_amount'] = (float) ($entertainmentStats->amount ?? 0);
         }
 
         return $result;