feat: [approval] 반려 이력 관리 기능 추가

- rejection_history JSON 컬럼으로 반려 이력 누적 저장
- 재상신 시 반려자, 사유, 일시를 이력에 기록
- 상세 페이지에 반려 이력 섹션 표시 (빨간 테두리)
- 수정 페이지에 이전 반려 이력 표시 (주황 배경)

app/Models/Approvals/Approval.php

@@ -23,6 +23,7 @@ class Approval extends Model
         'drafter_read_at' => 'datetime',
         'current_step' => 'integer',
         'resubmit_count' => 'integer',
+        'rejection_history' => 'array',
         'is_urgent' => 'boolean',
     ];
 
@@ -43,6 +44,7 @@ class Approval extends Model
         'drafter_read_at',
         'current_step',
         'resubmit_count',
+        'rejection_history',
         'attachments',
         'recall_reason',
         'parent_doc_id',

app/Services/ApprovalService.php

@@ -243,9 +243,24 @@ public function submit(int $id): Approval
                 throw new \InvalidArgumentException('결재선을 설정해주세요.');
             }
 
-            // 반려 후 재상신이면 모든 step 초기화 + 재상신 카운트 증가
+            // 반려 후 재상신이면 반려 이력 저장 + 모든 step 초기화 + 재상신 카운트 증가
             $isResubmit = $approval->status === Approval::STATUS_REJECTED;
             if ($isResubmit) {
+                // 반려 이력 저장
+                $rejectedStep = $approval->steps
+                    ->firstWhere('status', ApprovalStep::STATUS_REJECTED);
+                if ($rejectedStep) {
+                    $history = $approval->rejection_history ?? [];
+                    $history[] = [
+                        'round' => $approval->resubmit_count + 1,
+                        'approver_name' => $rejectedStep->approver_name ?? ($rejectedStep->approver?->name ?? ''),
+                        'approver_position' => $rejectedStep->approver_position ?? '',
+                        'comment' => $rejectedStep->comment,
+                        'rejected_at' => $rejectedStep->acted_at?->format('Y-m-d H:i:s'),
+                    ];
+                    $approval->rejection_history = $history;
+                }
+
                 $approval->steps()->update([
                     'status' => ApprovalStep::STATUS_PENDING,
                     'comment' => null,

resources/views/approvals/edit.blade.php

@@ -35,6 +35,28 @@
         </div>
     @endif
 
+    {{-- 반려 이력 (재상신 문서인 경우) --}}
+    @if(!empty($approval->rejection_history))
+        <div class="bg-orange-50 border border-orange-200 p-4 mb-6 rounded-lg" style="max-width: 960px; margin-left: auto; margin-right: auto;">
+            <h4 class="text-sm font-semibold text-orange-800 mb-2 flex items-center gap-2">
+                이전 반려 이력
+                <span class="inline-flex items-center px-1.5 py-0.5 rounded text-xs font-medium bg-orange-200 text-orange-700">{{ count($approval->rejection_history) }}회</span>
+            </h4>
+            <div class="space-y-2">
+                @foreach($approval->rejection_history as $history)
+                    <div class="text-sm border-l-2 border-orange-300 pl-3 py-1">
+                        <div class="flex items-center gap-2">
+                            <span class="text-xs font-medium text-orange-600">{{ $history['round'] ?? '-' }}차</span>
+                            <span class="font-medium text-gray-800">{{ $history['approver_name'] ?? '' }}</span>
+                            <span class="text-gray-400 text-xs">{{ $history['rejected_at'] ?? '' }}</span>
+                        </div>
+                        <p class="text-gray-600 mt-0.5">{{ $history['comment'] ?? '' }}</p>
+                    </div>
+                @endforeach
+            </div>
+        </div>
+    @endif
+
     <div class="mx-auto" style="max-width: 960px;">
         <div class="bg-white rounded-lg shadow-sm p-6">
             <h2 class="text-lg font-semibold text-gray-800 mb-4">문서 내용</h2>

resources/views/approvals/show.blade.php

@@ -92,6 +92,31 @@ class="bg-gray-600 hover:bg-gray-700 text-white px-4 py-2 rounded-lg transition
         </div>
     </div>
 
+    {{-- 반려 이력 --}}
+    @if(!empty($approval->rejection_history))
+    <div class="bg-white rounded-lg shadow-sm p-6 mb-6">
+        <h3 class="text-lg font-semibold text-gray-800 mb-3 flex items-center gap-2">
+            반려 이력
+            <span class="inline-flex items-center px-2 py-0.5 rounded-full text-xs font-medium bg-red-100 text-red-700">{{ count($approval->rejection_history) }}회</span>
+        </h3>
+        <div class="space-y-3">
+            @foreach($approval->rejection_history as $history)
+                <div class="border-l-3 border-red-300 pl-4 py-2" style="border-left: 3px solid #fca5a5;">
+                    <div class="flex items-center gap-2 text-sm">
+                        <span class="inline-flex items-center px-2 py-0.5 rounded text-xs font-medium bg-red-50 text-red-600">{{ $history['round'] ?? '-' }}차 반려</span>
+                        <span class="font-medium text-gray-800">{{ $history['approver_name'] ?? '' }}</span>
+                        @if(!empty($history['approver_position']))
+                            <span class="text-gray-400 text-xs">{{ $history['approver_position'] }}</span>
+                        @endif
+                        <span class="text-gray-400 text-xs">{{ $history['rejected_at'] ?? '' }}</span>
+                    </div>
+                    <p class="text-sm text-gray-700 mt-1">{{ $history['comment'] ?? '' }}</p>
+                </div>
+            @endforeach
+        </div>
+    </div>
+    @endif
+
     {{-- 결재 의견 --}}
     @php
         $stepsWithComments = $approval->steps->filter(fn($s) => $s->comment);