fix: [barobill] 홈택스 매입/매출 월정액을 무료(본사 부담)로 변경

- DEFAULT_MONTHLY_FEES hometax: 10000 → 0
- 월정액 0원일 때 "무료 (본사 제공)" 표시

app/Models/Barobill/BarobillSubscription.php

@@ -50,7 +50,7 @@ class BarobillSubscription extends Model
     public const DEFAULT_MONTHLY_FEES = [
         'bank_account' => 10000,
         'card' => 10000,
-        'hometax' => 10000,
+        'hometax' => 0, // 본사 부담 (무료 제공)
     ];
 
     /**

resources/views/barobill/billing/partials/subscription-table.blade.php

@@ -74,7 +74,11 @@
                             </span>
                         </td>
                         <td class="px-6 py-4 whitespace-nowrap text-right">
-                            <span class="text-sm font-medium text-gray-900">{{ number_format($subscription->monthly_fee) }}원</span>
+                            @if($subscription->monthly_fee > 0)
+                                <span class="text-sm font-medium text-gray-900">{{ number_format($subscription->monthly_fee) }}원</span>
+                            @else
+                                <span class="text-sm font-medium text-green-600">무료 (본사 제공)</span>
+                            @endif
                         </td>
                         <td class="px-6 py-4 whitespace-nowrap text-center">
                             <span class="text-sm text-gray-600">{{ $subscription->started_at?->format('Y-m-d') ?? '-' }}</span>