feat(API): 입금/출금 알림 Observer 추가 및 LoanController 수정

- DepositIssueObserver, WithdrawalIssueObserver 신규 추가
- TodayIssueObserverService에 입금/출금 핸들러 및 디버그 로그 추가
- TodayIssue 모델에 입금/출금 상수 추가
- AppServiceProvider에 Observer 등록
- ApprovalService에 기존 결재선 사용 시 수동 알림 트리거 추가
- LoanController ApiResponse::handle() → ApiResponse::success() 수정

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

app/Providers/AppServiceProvider.php

@@ -9,17 +9,21 @@
 use App\Models\Orders\Client;
 use App\Models\Orders\Order;
 use App\Models\Tenants\ApprovalStep;
+use App\Models\Tenants\Deposit;
 use App\Models\Tenants\ExpectedExpense;
 use App\Models\Tenants\Stock;
 use App\Models\Tenants\Tenant;
+use App\Models\Tenants\Withdrawal;
 use App\Observers\MenuObserver;
 use App\Observers\TenantObserver;
 use App\Observers\TodayIssue\ApprovalStepIssueObserver;
 use App\Observers\TodayIssue\BadDebtIssueObserver;
 use App\Observers\TodayIssue\ClientIssueObserver;
+use App\Observers\TodayIssue\DepositIssueObserver;
 use App\Observers\TodayIssue\ExpectedExpenseIssueObserver;
 use App\Observers\TodayIssue\OrderIssueObserver;
 use App\Observers\TodayIssue\StockIssueObserver;
+use App\Observers\TodayIssue\WithdrawalIssueObserver;
 use Illuminate\Database\Eloquent\Builder;
 use Illuminate\Database\Eloquent\Relations\Relation;
 use Illuminate\Support\Facades\DB;
@@ -77,5 +81,7 @@ public function boot(): void
         ExpectedExpense::observe(ExpectedExpenseIssueObserver::class);
         ApprovalStep::observe(ApprovalStepIssueObserver::class);
         Client::observe(ClientIssueObserver::class);
+        Deposit::observe(DepositIssueObserver::class);
+        Withdrawal::observe(WithdrawalIssueObserver::class);
     }
 }