feat: [재무] 어음 V8 + 상품권 접대비 연동 + 일반전표/계정과목 API

- Bill 확장 필드 (V8), Loan 상품권 카테고리/접대비 자동 연동
- GeneralJournalEntry CRUD, AccountSubject API
- 접대비/복리후생비 날짜 필터, 매출채권 soft delete 제외
- 바로빌 연동 API 엔드포인트 추가
- 부가세 상세 조회 API

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

app/Http/Requests/Loan/LoanUpdateRequest.php

@@ -2,7 +2,9 @@
 
 namespace App\Http\Requests\Loan;
 
+use App\Models\Tenants\Loan;
 use Illuminate\Foundation\Http\FormRequest;
+use Illuminate\Validation\Rule;
 
 class LoanUpdateRequest extends FormRequest
 {
@@ -27,6 +29,20 @@ public function rules(): array
             'amount' => ['sometimes', 'numeric', 'min:0', 'max:999999999999.99'],
             'purpose' => ['nullable', 'string', 'max:1000'],
             'withdrawal_id' => ['nullable', 'integer', 'exists:withdrawals,id'],
+            'category' => ['sometimes', 'string', Rule::in(Loan::CATEGORIES)],
+            'status' => ['sometimes', 'string', Rule::in(Loan::STATUSES)],
+            'settlement_date' => ['nullable', 'date', 'date_format:Y-m-d'],
+            'metadata' => ['nullable', 'array'],
+            'metadata.serial_number' => ['nullable', 'string', 'max:100'],
+            'metadata.cert_name' => ['nullable', 'string', 'max:200'],
+            'metadata.vendor_id' => ['nullable', 'string', 'max:50'],
+            'metadata.vendor_name' => ['nullable', 'string', 'max:200'],
+            'metadata.purchase_purpose' => ['nullable', 'string', 'max:50'],
+            'metadata.entertainment_expense' => ['nullable', 'string', 'max:50'],
+            'metadata.recipient_name' => ['nullable', 'string', 'max:100'],
+            'metadata.recipient_organization' => ['nullable', 'string', 'max:200'],
+            'metadata.usage_description' => ['nullable', 'string', 'max:1000'],
+            'metadata.memo' => ['nullable', 'string', 'max:2000'],
         ];
     }