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/api/kling.js

@@ -6,22 +6,6 @@ import { MaterialService } from './material'
 
 // ========== 辅助函数 ==========
 
-/**
- * 从视频中提取封面（可选操作）
- */
-async function extractVideoCoverOptional(file) {
-  try {
-    const { extractVideoCover } = await import('@/utils/video-cover')
-    const cover = await extractVideoCover(file, {
-      maxWidth: 800,
-      quality: 0.8
-    })
-    return cover.base64
-  } catch {
-    return null
-  }
-}
-
 /**
  * 执行人脸识别并返回结果
  */
@@ -103,9 +87,7 @@ export async function identifyUploadedVideo(videoFile) {
  * 上传视频并识别
  */
 export async function uploadAndIdentifyVideo(file) {
-  const coverBase64 = await extractVideoCoverOptional(file)
-
-  const uploadRes = await MaterialService.uploadFile(file, 'digital_human', coverBase64, null, null)
+  const uploadRes = await MaterialService.uploadFile(file, 'digital_human', null, null)
   if (uploadRes.code !== 0) {
     throw new Error(uploadRes.msg || '上传失败')
   }

frontend/app/web-gold/src/api/material.js

@@ -65,12 +65,11 @@ export const MaterialService = {
    * 上传文件
    * @param {File} file - 文件对象
    * @param {string} fileCategory - 文件分类（video/generate/audio/mix/voice）
-   * @param {string} coverBase64 - 视频封面 base64（可选，data URI 格式）
    * @param {number} duration - 视频时长（秒，可选，自动获取）
    * @param {number} groupId - 分组编号（可选）
    * @returns {Promise}
    */
-  async uploadFile(file, fileCategory, coverBase64 = null, duration = null, groupId = null) {
+  async uploadFile(file, fileCategory, duration = null, groupId = null) {
     if (duration === null && file.type.startsWith('video/')) {
       duration = await getVideoDuration(file);
     }
@@ -83,10 +82,6 @@ export const MaterialService = {
       formData.append('duration', duration.toString());
     }
 
-    if (coverBase64) {
-      formData.append('coverBase64', coverBase64)
-    }
-
     if (groupId !== null) {
       formData.append('groupId', groupId.toString())
     }