feat(API): Service 로직 개선

- EstimateService, ItemService 기능 추가
- OrderService 공정 연동 개선
- SalaryService, ReceivablesService 수정
- HandoverReportService, SiteBriefingService 추가
- Pricing 서비스 추가

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

app/Services/Estimate/EstimateService.php

@@ -24,7 +24,6 @@ public function __construct(
         CalculationEngine $calculationEngine,
         PricingService $pricingService
     ) {
-        parent::__construct();
         $this->modelSetService = $modelSetService;
         $this->calculationEngine = $calculationEngine;
         $this->pricingService = $pricingService;
@@ -362,6 +361,37 @@ protected function createEstimateItems(Estimate $estimate, array $bomItems, ?int
         return $totalAmount;
     }
 
+    /**
+     * 견적 통계 조회
+     */
+    public function stats(): array
+    {
+        $tenantId = $this->tenantId();
+
+        $stats = Estimate::query()
+            ->where('tenant_id', $tenantId)
+            ->selectRaw("
+                COUNT(*) as total,
+                SUM(CASE WHEN status = 'DRAFT' THEN 1 ELSE 0 END) as draft,
+                SUM(CASE WHEN status = 'SENT' THEN 1 ELSE 0 END) as sent,
+                SUM(CASE WHEN status = 'APPROVED' THEN 1 ELSE 0 END) as approved,
+                SUM(CASE WHEN status = 'REJECTED' THEN 1 ELSE 0 END) as rejected,
+                SUM(CASE WHEN status = 'EXPIRED' THEN 1 ELSE 0 END) as expired,
+                SUM(total_amount) as total_amount
+            ")
+            ->first();
+
+        return [
+            'total' => (int) $stats->total,
+            'draft' => (int) $stats->draft,
+            'sent' => (int) $stats->sent,
+            'approved' => (int) $stats->approved,
+            'rejected' => (int) $stats->rejected,
+            'expired' => (int) $stats->expired,
+            'total_amount' => (float) ($stats->total_amount ?? 0),
+        ];
+    }
+
     /**
      * 계산 결과 요약
      */