feat: 优化新闻添加表单布局，调整标题和摘要字段为网格布局，更新内容字段为Markdown编辑器；调整添加新闻对话框宽度

src/views/news/components/add.vue

@@ -85,26 +85,18 @@ function resetForm() {
           @update:model-value="evt => (formModel.thumbnailId = evt.length > 0 ? evt[0] : undefined)"
         />
       </NFormItem>
-      <NFormItem label="标题" path="title">
-        <NInput v-model:value="formModel.title" placeholder="请输入标题" />
-      </NFormItem>
+      <NGrid cols="2" x-gap="16px">
+        <NFormItemGi label="标题" path="title">
+          <NInput v-model:value="formModel.title" placeholder="请输入标题" />
+        </NFormItemGi>
 
-      <NFormItem label="摘要" path="summary">
-        <NInput
-          v-model:value="formModel.summary"
-          type="textarea"
-          placeholder="请输入摘要"
-          :autosize="{ minRows: 3, maxRows: 5 }"
-        />
-      </NFormItem>
+        <NFormItemGi label="摘要" path="summary">
+          <NInput v-model:value="formModel.summary" placeholder="请输入摘要" />
+        </NFormItemGi>
+      </NGrid>
 
       <NFormItem label="内容" path="content">
-        <NInput
-          v-model:value="formModel.content"
-          type="textarea"
-          placeholder="请输入内容"
-          :autosize="{ minRows: 5, maxRows: 10 }"
-        />
+        <MarkdownEditor v-model:value="formModel.content" placeholder="请输入新闻内容" :preview="false" />
       </NFormItem>
 
       <NGrid cols="2" x-gap="16px">

src/views/news/index.vue

@@ -77,7 +77,7 @@ function handleAdd() {
   dialog.create({
     title: '添加新闻',
     showIcon: false,
-    style: { width: '800px' },
+    style: { width: '1000px' },
     content: () =>
       h(Add, {
         onClose: () => {