fix: FormRequest에 process_ids, priority 필드 추가

- CreateProductionOrderRequest에 누락된 필드 추가
- process_id, process_ids, priority 검증 규칙 추가
- $request->validated()에서 필터링되는 문제 해결
- 공정별 다중 작업지시 생성 정상 동작

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

app/Http/Requests/Order/CreateProductionOrderRequest.php

@@ -16,6 +16,10 @@ public function authorize(): bool
     public function rules(): array
     {
         return [
+            'process_id' => 'nullable|integer|exists:processes,id',
+            'process_ids' => 'nullable|array',
+            'process_ids.*' => 'integer|exists:processes,id',
+            'priority' => 'nullable|string',
             'process_type' => ['nullable', Rule::in(WorkOrder::PROCESS_TYPES)],
             'assignee_id' => 'nullable|integer|exists:users,id',
             'team_id' => 'nullable|integer|exists:departments,id',