style(frontend): 上传页让「选择文件夹上传」与「选择文件」按钮同行显示

将独立成行的文件夹上传按钮并入 t-upload file-flow 的 trigger 插槽，
与「选择文件」按钮并排一行，消除上传区顶部孤零按钮的松散观感。

- 文件夹上传：@click.stop.prevent 触发独立 webkitdirectory input
- 选择文件：调用官方实例方法 uploadRef.triggerUpload() 打开多文件选择器
- 两个入口各自触发、互不误触；拖拽卡与底部上传按钮逻辑保持不变

frontend/src/views/DocUpload.vue

@@ -27,14 +27,19 @@
     <!-- 上传模式 Tab -->
     <t-tabs v-model="uploadMode">
       <t-tab-panel value="file" label="📄 文件上传">
-        <div class="folder-upload-bar">
-          <t-button variant="outline" size="small" :loading="folderUploading" @click="pickFolder">📁 选择文件夹上传</t-button>
+        <t-upload ref="uploadRef" :auto-upload="false" theme="file-flow" multiple :before-upload="beforeFileUpload"
+          :request-method="handleFileUpload" accept=".pdf,.doc,.docx,.xls,.xlsx,.ppt,.pptx,.txt,.md,.json,.csv,.html,.xml,.rtf"
+          :size-limit="{ size: 50, unit: 'MB', message: '文件大小不能超过 50MB' }">
+          <template #trigger>
+            <div class="upload-trigger-row">
+              <t-button variant="outline" :loading="folderUploading" @click.stop.prevent="pickFolder">📁 选择文件夹上传</t-button>
+              <t-button variant="outline" @click.stop.prevent="pickFile">📄 选择文件</t-button>
               <span v-if="folderUploading" class="folder-progress">上传中 {{ folderProgress ?? 0 }}%</span>
-          <input ref="folderInput" type="file" webkitdirectory style="display:none;" @change="onFolderSelected" />
             </div>
-        <t-upload :auto-upload="false" theme="file-flow" multiple :before-upload="beforeFileUpload"
-          :request-method="handleFileUpload" accept=".pdf,.doc,.docx,.xls,.xlsx,.ppt,.pptx,.txt,.md,.json,.csv,.html,.xml,.rtf"
-          :size-limit="{ size: 50, unit: 'MB', message: '文件大小不能超过 50MB' }" />
+          </template>
+        </t-upload>
+        <!-- 独立的文件夹选择隐藏 input（不随 t-upload 的 trigger 打开） -->
+        <input ref="folderInput" type="file" webkitdirectory style="display:none;" @change="onFolderSelected" />
       </t-tab-panel>
       <t-tab-panel value="text" label="📝 文本">
         <t-textarea v-model="textContent" placeholder="粘贴文本内容..." :autosize="{ minRows: 6, maxRows: 12 }" />
@@ -54,7 +59,7 @@
 <script setup lang="ts">
 import { ref, computed, watch, h } from 'vue'
 import { DialogPlugin } from 'tdesign-vue-next'
-import type { UploadFile } from 'tdesign-vue-next'
+import type { UploadFile, UploadInstanceFunctions } from 'tdesign-vue-next'
 import { useCategoryStore } from '@/stores/category'
 import { useDocumentStore } from '@/stores/document'
 import { uploadFile, uploadMarkdown, uploadJsonBasic, uploadFolder } from '@/api/upload'
@@ -68,6 +73,9 @@ const uploadMode = ref('file')
 const uploadCategory = ref('')
 const uploading = ref(false)
 
+// t-upload 实例（用于自定义 trigger 时打开文件选择器）
+const uploadRef = ref<UploadInstanceFunctions>()
+
 // 目标目录（value 形如 'folder:xxx'，空 = 分类根）
 const uploadFolderId = ref('')
 const folderTreeData = ref<any[]>([])
@@ -224,7 +232,13 @@ function onFolderChange(_value: any, ctx: any) {
   }
 }
 
-// ==================== 文件夹上传 ====================
+// ==================== 上传触发（自定义 trigger 行的两个入口） ====================
+/** 选择文件：调用 t-upload 实例方法打开文件选择器 */
+function pickFile() {
+  uploadRef.value?.triggerUpload?.()
+}
+
+/** 选择文件夹：触发独立的 webkitdirectory input */
 function pickFolder() {
   folderInput.value?.click()
 }
@@ -332,6 +346,6 @@ async function onFolderSelected(e: Event) {
 <style scoped>
 .upload-meta { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; padding: 12px; background: var(--color-bg-subtle); border-radius: 8px; border: 1px solid var(--color-border); margin-bottom: 16px; }
 .tag-input-wrapper { display: flex; flex-wrap: wrap; gap: 4px; align-items: center; flex: 1; padding: 4px 8px; border: 1px solid var(--color-border); border-radius: 4px; background: var(--td-bg-color-container); }
-.folder-upload-bar { display: flex; align-items: center; gap: 8px; margin-bottom: 8px; }
+.upload-trigger-row { display: flex; align-items: center; gap: 8px; }
 .folder-progress { font-size: 12px; color: var(--td-text-color-secondary); }
 </style>