fix: [loan] getCategoryBreakdown SQL alias 충돌 수정

- outstanding_amount → cat_outstanding alias 변경 (Loan accessor 충돌 방지)

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

app/Services/LoanService.php

@@ -483,8 +483,10 @@ private function getCategoryBreakdown(int $tenantId, ?string $startDate = null,
             $query->where('loan_date', '<=', $endDate);
         }
 
+        // NOTE: SQL alias를 'cat_outstanding'으로 사용 — Loan 모델의
+        // getOutstandingAmountAttribute() accessor와 이름 충돌 방지
         $stats = $query
-            ->selectRaw('category, COUNT(*) as total_count, SUM(amount - COALESCE(settlement_amount, 0)) as outstanding_amount')
+            ->selectRaw('category, COUNT(*) as total_count, SUM(amount - COALESCE(settlement_amount, 0)) as cat_outstanding')
             ->selectRaw('SUM(CASE WHEN purpose IS NULL OR purpose = \'\' THEN 1 ELSE 0 END) as unverified_count')
             ->groupBy('category')
             ->get();
@@ -493,7 +495,7 @@ private function getCategoryBreakdown(int $tenantId, ?string $startDate = null,
             $cat = $stat->category ?? Loan::CATEGORY_CARD;
             if (isset($breakdown[$cat])) {
                 $breakdown[$cat] = [
-                    'outstanding_amount' => (float) $stat->outstanding_amount,
+                    'outstanding_amount' => (float) $stat->cat_outstanding,
                     'total_count' => (int) $stat->total_count,
                     'unverified_count' => (int) $stat->unverified_count,
                 ];