feat: [approval] Document ↔ Approval 브릿지 연동 (Phase 4.2)

- Approval 모델에 linkable morphTo 관계 추가
- DocumentService: 상신 시 Approval 자동 생성 + approval_steps 변환
- ApprovalService: 승인/반려/회수 시 Document 상태 동기화
- approvals 테이블에 linkable_type, linkable_id 컬럼 마이그레이션

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

app/Services/DocumentService.php

@@ -7,6 +7,10 @@
 use App\Models\Documents\DocumentAttachment;
 use App\Models\Documents\DocumentData;
 use App\Models\Documents\DocumentTemplate;
+use App\Models\Tenants\Approval;
+use App\Models\Tenants\ApprovalForm;
+use App\Models\Tenants\ApprovalLine;
+use App\Models\Tenants\ApprovalStep;
 use Illuminate\Contracts\Pagination\LengthAwarePaginator;
 use Illuminate\Support\Facades\DB;
 use Symfony\Component\HttpKernel\Exception\BadRequestHttpException;
@@ -275,6 +279,9 @@ public function submit(int $id): Document
             $document->updated_by = $userId;
             $document->save();
 
+            // Approval 시스템 브릿지: 결재함(/approval/inbox)에 표시되도록 Approval 자동 생성
+            $this->createApprovalBridge($document);
+
             return $document->fresh([
                 'template:id,name,category',
                 'approvals.user:id,name',
@@ -283,6 +290,78 @@ public function submit(int $id): Document
         });
     }
 
+    /**
+     * Document → Approval 브릿지 생성
+     * Document 상신 시 Approval 레코드를 자동 생성하여 /approval/inbox에 표시
+     */
+    private function createApprovalBridge(Document $document): void
+    {
+        $form = ApprovalForm::where('code', 'document')
+            ->where('tenant_id', $document->tenant_id)
+            ->first();
+
+        if (! $form) {
+            return; // 문서 결재 양식 미등록 시 스킵 (기존 동작 유지)
+        }
+
+        // 기존 브릿지가 있으면 스킵 (재상신 방지)
+        $existingApproval = Approval::where('linkable_type', Document::class)
+            ->where('linkable_id', $document->id)
+            ->whereNotIn('status', [Approval::STATUS_CANCELLED])
+            ->first();
+
+        if ($existingApproval) {
+            return;
+        }
+
+        // 문서번호 생성 (Approval 체계)
+        $today = now()->format('Ymd');
+        $lastNumber = Approval::where('tenant_id', $document->tenant_id)
+            ->where('document_number', 'like', "AP-{$today}-%")
+            ->orderByDesc('document_number')
+            ->value('document_number');
+
+        $seq = 1;
+        if ($lastNumber && preg_match('/AP-\d{8}-(\d{4})/', $lastNumber, $matches)) {
+            $seq = (int) $matches[1] + 1;
+        }
+        $documentNumber = sprintf('AP-%s-%04d', $today, $seq);
+
+        $approval = Approval::create([
+            'tenant_id' => $document->tenant_id,
+            'document_number' => $documentNumber,
+            'form_id' => $form->id,
+            'title' => $document->title,
+            'content' => [
+                'document_id' => $document->id,
+                'template_id' => $document->template_id,
+                'document_no' => $document->document_no,
+            ],
+            'status' => Approval::STATUS_PENDING,
+            'drafter_id' => $document->created_by,
+            'drafted_at' => now(),
+            'current_step' => 1,
+            'linkable_type' => Document::class,
+            'linkable_id' => $document->id,
+            'created_by' => $document->updated_by ?? $document->created_by,
+        ]);
+
+        // document_approvals → approval_steps 변환
+        $docApprovals = $document->approvals()
+            ->orderBy('step')
+            ->get();
+
+        foreach ($docApprovals as $docApproval) {
+            ApprovalStep::create([
+                'approval_id' => $approval->id,
+                'step_order' => $docApproval->step,
+                'step_type' => ApprovalLine::STEP_TYPE_APPROVAL,
+                'approver_id' => $docApproval->user_id,
+                'status' => ApprovalStep::STATUS_PENDING,
+            ]);
+        }
+    }
+
     /**
      * 결재 승인
      */