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/Http/Requests/Inspection/InspectionStoreRequest.php

@@ -22,6 +22,7 @@ public function rules(): array
                 Inspection::TYPE_FQC,
             ])],
             'lot_no' => ['required', 'string', 'max:50'],
+            'work_order_id' => ['nullable', 'integer', 'exists:work_orders,id'],
             'item_name' => ['nullable', 'string', 'max:200'],
             'process_name' => ['nullable', 'string', 'max:100'],
             'quantity' => ['nullable', 'numeric', 'min:0'],