feat(material): remove video cover extraction and simplify upload API

- Remove extractVideoCoverOptional function and related video cover processing
- Update MaterialService.uploadFile method signature to remove coverBase64 parameter
- Simplify uploadAndIdentifyVideo function by removing cover generation logic
- Remove loading indicator from VideoSelector component during video preview
- Add presignGetUrlWithProcess method to FileClient interface for processed file URLs
- Add logging support to S3FileClient implementation

frontend/app/web-gold/src/views/dh/Video.vue

@@ -12,7 +12,6 @@ import { InboxOutlined, SoundOutlined, LoadingOutlined } from '@ant-design/icons
 import { VoiceService } from '@/api/voice'
 import { MaterialService } from '@/api/material'
 import { createDigitalHumanTask, getDigitalHumanTask, cancelTask, retryTask } from '@/api/digitalHuman'
-import { extractVideoCover } from '@/utils/video-cover'
 import { useUpload } from '@/composables/useUpload'
 import { DEFAULT_VOICE_PROVIDER } from '@/config/voiceConfig'
 
@@ -391,19 +390,6 @@ const handleVideoUpload = async (file) => {
   try {
     uploadedVideo.value = await toDataURL(file)
     uploadedVideoFile.value = file // 保存文件对象
-
-    // 提取视频封面
-    try {
-      const cover = await extractVideoCover(file, {
-        maxWidth: 800,
-        quality: 0.8
-      })
-      uploadedVideoFile.value.coverBase64 = cover.base64 // 保存封面到文件对象
-    } catch (coverError) {
-      console.warn('视频封面提取失败:', coverError)
-      // 封面提取失败不影响主流程
-    }
-
     message.success('视频上传成功')
   } catch (error) {
     console.error('视频上传失败:', error)
@@ -513,14 +499,10 @@ const generateVideo = async () => {
 // 上传视频文件到后端
 const uploadVideoFile = async (file) => {
   try {
-    // 获取封面base64
-    const coverBase64 = file.coverBase64 || null
-
     // 使用useUpload Hook上传文件
     const fileId = await upload(file, {
       fileCategory: 'video',
       groupId: null, // 数字人视频模块不使用groupId
-      coverBase64,
       onStart: () => {},
       onProgress: () => {},
       onSuccess: (id) => {

frontend/app/web-gold/src/views/dh/VoiceCopy.vue

@@ -375,7 +375,6 @@ async function handleCustomUpload(options) {
     const fileId = await upload(file, {
       fileCategory: 'voice',
       groupId: null,
-      coverBase64: null,
       onSuccess: async function(id, fileUrl) {
         formData.fileId = id
         formData.fileUrl = fileUrl

frontend/app/web-gold/src/views/material/MaterialListNew.vue

@@ -152,8 +152,8 @@
                 <!-- 预览图 -->
                 <div class="material-item__preview">
                   <img
-                    v-if="file.coverBase64"
-                    :src="file.coverBase64"
+                    v-if="file.previewUrl"
+                    :src="file.previewUrl"
                     :alt="file.fileName"
                     @error="handleImageError"
                     loading="lazy"

frontend/app/web-gold/src/views/material/Mix.vue

@@ -159,8 +159,8 @@
                       <template #item="{ element: candidate, index: cIndex }">
                         <div class="candidate-thumb">
                           <img
-                            v-if="getFileById(candidate.fileId)?.coverBase64"
-                            :src="getFileById(candidate.fileId).coverBase64"
+                            v-if="getFileById(candidate.fileId)?.previewUrl"
+                            :src="getFileById(candidate.fileId).previewUrl"
                           />
                           <div v-else class="thumb-placeholder">
                             <VideoCameraOutlined />

frontend/app/web-gold/src/views/material/components/SceneSelectorModal.vue

@@ -69,7 +69,7 @@
           @dblclick="handleQuickConfirm(file)"
         >
           <div class="card-cover">
-            <img v-if="file.coverBase64" :src="file.coverBase64" />
+            <img v-if="file.previewUrl" :src="file.previewUrl" />
             <div v-else class="cover-placeholder">
               <VideoCameraOutlined />
             </div>