refactor: [세금계산서/바로빌] ApiResponse::handle() 클로저 패턴으로 통일

- BarobillSettingController: show/save/testConnection 클로저 방식 전환
- TaxInvoiceController: 전체 액션(index/show/store/update/destroy/issue/bulkIssue/cancel/checkStatus/summary) 클로저 방식 전환
- 중간 변수 할당 제거, 일관된 응답 패턴 적용

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

app/Http/Controllers/Api/V1/BarobillSettingController.php

@@ -18,12 +18,9 @@ public function __construct(
      */
     public function show()
     {
-        $setting = $this->barobillService->getSetting();
-
-        return ApiResponse::handle(
-            data: $setting,
-            message: __('message.fetched')
-        );
+        return ApiResponse::handle(function () {
+            return $this->barobillService->getSetting();
+        }, __('message.fetched'));
     }
 
     /**
@@ -31,12 +28,9 @@ public function show()
      */
     public function save(SaveBarobillSettingRequest $request)
     {
-        $setting = $this->barobillService->saveSetting($request->validated());
-
-        return ApiResponse::handle(
-            data: $setting,
-            message: __('message.saved')
-        );
+        return ApiResponse::handle(function () use ($request) {
+            return $this->barobillService->saveSetting($request->validated());
+        }, __('message.saved'));
     }
 
     /**
@@ -44,11 +38,8 @@ public function save(SaveBarobillSettingRequest $request)
      */
     public function testConnection()
     {
-        $result = $this->barobillService->testConnection();
-
-        return ApiResponse::handle(
-            data: $result,
-            message: __('message.barobill.connection_success')
-        );
+        return ApiResponse::handle(function () {
+            return $this->barobillService->testConnection();
+        }, __('message.barobill.connection_success'));
     }
 }