refactor: 重构产品相关Mapper

- 空值处理与类型控制：为相关关系型字段的数据处理添加空值处理与类型控制
- 调整目录结构：将文件目录按照实际查询划分为Product和ProductList两个文件

server/mappers/documentMapper.test.ts

@@ -1,9 +1,5 @@
 import { describe, test, expect } from 'vitest';
-import {
-  toProductDocumentView,
-  toDocumentListView,
-  toDocumentTypeView,
-} from './documentMapper';
+import { toDocumentListView, toDocumentTypeView } from './documentMapper';
 
 /**
  * 单元测试: toDocumentTypeView
@@ -46,63 +42,6 @@ describe('toDocumentTypeView', () => {
     });
   });
 });
-/**
- * 单元测试: toProductDocumentView
- */
-describe('toProductDocumentView', () => {
-  const baseData: ProductDocument = {
-    id: 1,
-    file: {
-      id: 'rand-om__-uuid-1234',
-      filename_download: 'document.pdf',
-      filesize: 2048,
-    },
-    translations: [{ id: 10, title: 'Document Title' }],
-  };
-
-  test('convert raw data with fileMeta to ProductDocumentView correctly', () => {
-    const rawData: ProductDocument = { ...baseData };
-    expect(toProductDocumentView(rawData)).toEqual({
-      id: '1',
-      fileId: 'rand-om__-uuid-1234',
-      filename: 'document.pdf',
-      title: 'Document Title',
-      url: '/api/assets/rand-om__-uuid-1234',
-      size: 2048,
-    });
-  });
-
-  test('convert raw data with fileId', () => {
-    const rawData: ProductDocument = {
-      ...baseData,
-      file: 'rand-om__-uuid-1234',
-    };
-
-    expect(toProductDocumentView(rawData)).toEqual({
-      id: '1',
-      fileId: '',
-      filename: '',
-      title: 'Document Title',
-      url: '/api/assets/',
-      size: 0,
-    });
-  });
-
-  test('convert raw data with missing translations', () => {
-    const rawData: ProductDocument = {
-      ...baseData,
-      translations: [],
-    };
-    expect(toProductDocumentView(rawData)).toEqual({
-      id: '1',
-      fileId: 'rand-om__-uuid-1234',
-      filename: 'document.pdf',
-      title: '',
-      url: '/api/assets/rand-om__-uuid-1234',
-      size: 2048,
-    });
-  });
-});
 
 /**
  * 单元测试: toDocumentListView