feat: Phase 8 SaaS 확장 - 구독관리/결제내역 API 추가

- 사용량 조회 API (GET /subscriptions/usage)
- 데이터 내보내기 API (POST/GET /subscriptions/export)
- 결제 명세서 API (GET /payments/{id}/statement)
- DataExport 모델 및 마이그레이션 추가

app/Services/SubscriptionService.php

@@ -2,12 +2,15 @@
 
 namespace App\Services;
 
+use App\Models\Tenants\DataExport;
 use App\Models\Tenants\Payment;
 use App\Models\Tenants\Plan;
 use App\Models\Tenants\Subscription;
+use App\Models\Tenants\Tenant;
 use Illuminate\Contracts\Pagination\LengthAwarePaginator;
 use Illuminate\Support\Facades\DB;
 use Symfony\Component\HttpKernel\Exception\BadRequestHttpException;
+use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
 
 class SubscriptionService extends Service
 {
@@ -294,4 +297,136 @@ public function resume(int $id): Subscription
 
         return $subscription->fresh(['plan']);
     }
+
+    // =========================================================================
+    // 사용량 조회
+    // =========================================================================
+
+    /**
+     * 사용량 조회
+     */
+    public function usage(): array
+    {
+        $tenantId = $this->tenantId();
+
+        $tenant = Tenant::with(['subscription.plan'])->findOrFail($tenantId);
+
+        // 사용자 수
+        $userCount = $tenant->users()->count();
+        $maxUsers = $tenant->max_users ?? 0;
+
+        // 저장공간
+        $storageUsed = $tenant->storage_used ?? 0;
+        $storageLimit = $tenant->storage_limit ?? 0;
+
+        // 구독 정보
+        $subscription = $tenant->subscription;
+        $remainingDays = null;
+        $planName = null;
+
+        if ($subscription && $subscription->is_valid) {
+            $remainingDays = $subscription->remaining_days;
+            $planName = $subscription->plan?->name;
+        }
+
+        return [
+            'users' => [
+                'used' => $userCount,
+                'limit' => $maxUsers,
+                'percentage' => $maxUsers > 0 ? round(($userCount / $maxUsers) * 100, 1) : 0,
+            ],
+            'storage' => [
+                'used' => $storageUsed,
+                'used_formatted' => $tenant->getStorageUsedFormatted(),
+                'limit' => $storageLimit,
+                'limit_formatted' => $tenant->getStorageLimitFormatted(),
+                'percentage' => $storageLimit > 0 ? round(($storageUsed / $storageLimit) * 100, 1) : 0,
+            ],
+            'subscription' => [
+                'plan' => $planName,
+                'status' => $subscription?->status,
+                'remaining_days' => $remainingDays,
+                'started_at' => $subscription?->started_at?->toDateString(),
+                'ended_at' => $subscription?->ended_at?->toDateString(),
+            ],
+        ];
+    }
+
+    // =========================================================================
+    // 데이터 내보내기
+    // =========================================================================
+
+    /**
+     * 내보내기 요청 생성
+     */
+    public function createExport(array $data): DataExport
+    {
+        $tenantId = $this->tenantId();
+        $userId = $this->apiUserId();
+
+        // 진행 중인 내보내기가 있는지 확인
+        $pendingExport = DataExport::where('tenant_id', $tenantId)
+            ->whereIn('status', [DataExport::STATUS_PENDING, DataExport::STATUS_PROCESSING])
+            ->first();
+
+        if ($pendingExport) {
+            throw new BadRequestHttpException(__('error.export.already_in_progress'));
+        }
+
+        $export = DataExport::create([
+            'tenant_id' => $tenantId,
+            'export_type' => $data['export_type'] ?? DataExport::TYPE_ALL,
+            'status' => DataExport::STATUS_PENDING,
+            'options' => $data['options'] ?? null,
+            'created_by' => $userId,
+        ]);
+
+        // TODO: 비동기 Job 디스패치
+        // dispatch(new ProcessDataExport($export));
+
+        return $export;
+    }
+
+    /**
+     * 내보내기 상태 조회
+     */
+    public function getExport(int $id): DataExport
+    {
+        $tenantId = $this->tenantId();
+
+        $export = DataExport::where('tenant_id', $tenantId)->find($id);
+
+        if (! $export) {
+            throw new NotFoundHttpException(__('error.export.not_found'));
+        }
+
+        return $export;
+    }
+
+    /**
+     * 내보내기 목록 조회
+     */
+    public function getExports(array $params = []): LengthAwarePaginator
+    {
+        $tenantId = $this->tenantId();
+
+        $query = DataExport::where('tenant_id', $tenantId)
+            ->with('creator:id,name,email');
+
+        // 상태 필터
+        if (! empty($params['status'])) {
+            $query->where('status', $params['status']);
+        }
+
+        // 유형 필터
+        if (! empty($params['export_type'])) {
+            $query->where('export_type', $params['export_type']);
+        }
+
+        $query->orderBy('created_at', 'desc');
+
+        $perPage = $params['per_page'] ?? 20;
+
+        return $query->paginate($perPage);
+    }
 }