feat: MaterialApi.php Swagger 점검 및 개선 (Phase 3-2)

- MaterialStoreRequest.php 생성 (검증 로직 분리)
- MaterialUpdateRequest.php 생성 (검증 로직 분리)
- MaterialApi.php 경로 수정 (/api/v1/products/materials)
- MaterialController.php Swagger 주석 제거, FormRequest 적용
- lang/ko/message.php material 메시지 키 추가
- SAM API Development Rules 준수 완료

app/Http/Requests/Material/MaterialUpdateRequest.php

@@ -0,0 +1,32 @@
+<?php
+
+namespace App\Http\Requests\Material;
+
+use Illuminate\Foundation\Http\FormRequest;
+
+class MaterialUpdateRequest extends FormRequest
+{
+    public function authorize(): bool
+    {
+        return true;
+    }
+
+    public function rules(): array
+    {
+        return [
+            'category_id' => 'nullable|integer',
+            'name' => 'sometimes|string|max:100',
+            'unit' => 'sometimes|string|max:20',
+            'is_inspection' => 'nullable|in:Y,N',
+            'search_tag' => 'nullable|string|max:255',
+            'remarks' => 'nullable|string|max:500',
+            'attributes' => 'nullable|array',
+            'attributes.*.label' => 'required|string|max:50',
+            'attributes.*.value' => 'required|string|max:100',
+            'attributes.*.unit' => 'nullable|string|max:20',
+            'options' => 'nullable|array',
+            'material_code' => 'nullable|string|max:30',
+            'specification' => 'nullable|string|max:255',
+        ];
+    }
+}