fix: [주문/재고생산] item_id 검증 제거 및 options.reg_date validation 추가

app/Http/Requests/Order/UpdateOrderRequest.php

@@ -51,6 +51,7 @@ public function rules(): array
             'options.manager_name' => 'nullable|string|max:100',
             'options.production_reason' => 'nullable|string|max:500',
             'options.target_stock_qty' => 'nullable|numeric|min:0',
+            'options.reg_date' => 'nullable|date',
 
             // 절곡품 LOT 정보 (STOCK 전용)
             'options.bending_lot' => 'nullable|array',
@@ -64,7 +65,7 @@ public function rules(): array
 
             // 품목 배열 (전체 교체)
             'items' => 'nullable|array',
-            'items.*.item_id' => 'nullable|integer|exists:items,id',
+            'items.*.item_id' => 'nullable|integer',
             'items.*.item_code' => 'nullable|string|max:50',
             'items.*.item_name' => 'sometimes|required|string|max:200',
             'items.*.specification' => 'nullable|string|max:500',