移除"从素材提取尾帧"功能（上游已实现类似功能）

- 移除 ExtractFrame handler 和路由
- 移除 AssetService 中的 ExtractFrameFromAsset 方法
- 移除 FFmpeg 中的 ExtractFrame 方法
- 移除前端 extractFrame API 和相关 UI

Co-Authored-By: Claude <noreply@anthropic.com>

web/src/api/asset.ts

@@ -43,9 +43,5 @@ export const assetAPI = {
 
   importFromVideo(videoGenId: number) {
     return request.post<Asset>(`/assets/import/video/${videoGenId}`)
-  },
-
-  extractFrame(assetId: number, data: { position: string; storyboard_id: number; frame_type?: string }) {
-    return request.post(`/assets/${assetId}/extract-frame`, data)
   }
 }

web/src/views/drama/ProfessionalEditor.vue

@@ -239,24 +239,6 @@
                     }}</span>
                 </div>
 
-                <!-- 从素材提取尾帧 -->
-                <div class="extract-frame-section" v-if="selectedFrameType === 'first'" style="margin: 12px 0; padding: 12px; background: #f5f7fa; border-radius: 8px;">
-                  <div class="section-label" style="margin-bottom: 8px;">从素材提取尾帧（用于画面连续性）</div>
-                  <div style="display: flex; gap: 10px; align-items: center;">
-                    <el-select v-model="selectedAssetForExtract" placeholder="选择视频素材" style="width: 300px;" size="small">
-                      <el-option
-                        v-for="asset in videoAssets"
-                        :key="asset.id"
-                        :label="`镜头 #${asset.storyboard_num || asset.id} - ${asset.name}`"
-                        :value="asset.id"
-                      />
-                    </el-select>
-                    <el-button type="primary" size="small" :loading="extractingFrame" :disabled="!selectedAssetForExtract" @click="extractLastFrame">
-                      提取尾帧
-                    </el-button>
-                  </div>
-                </div>
-
                 <!-- 提示词区域 -->
                 <div class="prompt-section">
                   <div class="section-label">
@@ -1004,8 +986,6 @@ const generatingImage = ref(false)
 const generatedImages = ref<ImageGeneration[]>([])
 const isSwitchingFrameType = ref(false) // 标志位：是否正在切换帧类型
 const loadingImages = ref(false)
-const selectedAssetForExtract = ref<number | null>(null) // 选中的素材用于提取尾帧
-const extractingFrame = ref(false) // 是否正在提取尾帧
 let pollingTimer: any = null
 let pollingFrameType: FrameType | null = null // 记录正在轮询的帧类型
 
@@ -1722,35 +1702,6 @@ const generateFrameImage = async () => {
   }
 }
 
-// 从素材提取尾帧
-const extractLastFrame = async () => {
-  if (!selectedAssetForExtract.value || !currentStoryboard.value) {
-    ElMessage.warning('请先选择视频素材')
-    return
-  }
-
-  extractingFrame.value = true
-  try {
-    const result = await assetAPI.extractFrame(selectedAssetForExtract.value, {
-      position: 'last',
-      storyboard_id: currentStoryboard.value.id,
-      frame_type: 'first' // 提取的尾帧用作当前分镜的首帧
-    })
-
-    ElMessage.success('尾帧提取成功，已添加到首帧图片列表')
-
-    // 刷新图片列表
-    await loadStoryboardImages(currentStoryboard.value!.id, 'first')
-
-    // 清空选择
-    selectedAssetForExtract.value = null
-  } catch (error: any) {
-    ElMessage.error('提取失败: ' + (error.message || '未知错误'))
-  } finally {
-    extractingFrame.value = false
-  }
-}
-
 // 删除图片生成记录
 const deleteImage = async (imageId: number) => {
   try {