feat: [quote/quality] Phase 2B 견적 product_code 자동추출 + inspections work_order_id FK

- QuoteService: extractProductCodeFromInputs() 추가, store/update에서 자동 추출
- BackfillQuoteProductCodeCommand: 기존 quotes 25건 product_code 보정
- inspections 테이블에 work_order_id FK 마이그레이션 (nullable, nullOnDelete)
- Inspection↔WorkOrder 양방향 관계 추가
- InspectionService: store/show/index에 work_order_id 처리 + transformToFrontend
- InspectionStoreRequest: work_order_id 검증 규칙 추가

app/Models/Production/WorkOrder.php

@@ -6,6 +6,7 @@
 use App\Models\Members\User;
 use App\Models\Orders\Order;
 use App\Models\Process;
+use App\Models\Qualitys\Inspection;
 use App\Models\Tenants\Department;
 use App\Models\Tenants\Shipment;
 use App\Traits\Auditable;
@@ -234,6 +235,14 @@ public function shipments(): HasMany
         return $this->hasMany(Shipment::class);
     }
 
+    /**
+     * 품질검사 (IQC/PQC/FQC)
+     */
+    public function inspections(): HasMany
+    {
+        return $this->hasMany(Inspection::class);
+    }
+
     /**
      * 생성자
      */