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>

application/services/asset_service.go

@@ -2,11 +2,8 @@ package services
 
 import (
 	"fmt"
-	"os"
-	"path/filepath"
 	"strconv"
 	"strings"
-	"time"
 
 	models "github.com/drama-generator/backend/domain/models"
 	"github.com/drama-generator/backend/infrastructure/external/ffmpeg"
@@ -326,120 +323,3 @@ func (s *AssetService) ImportFromVideoGen(videoGenID uint) (*models.Asset, error
 
 	return asset, nil
 }
-
-// ExtractFrameRequest 视频帧提取请求
-type ExtractFrameRequest struct {
-	Position     string `json:"position"`      // "first" 或 "last"
-	StoryboardID uint   `json:"storyboard_id"` // 关联的分镜 ID
-	FrameType    string `json:"frame_type"`    // image_generations 的帧类型，默认 "first"
-}
-
-// ExtractFrameFromAsset 从视频素材中提取帧并保存到 image_generations 表
-func (s *AssetService) ExtractFrameFromAsset(assetID uint, req *ExtractFrameRequest) (*models.ImageGeneration, error) {
-	// 获取素材
-	var asset models.Asset
-	if err := s.db.First(&asset, assetID).Error; err != nil {
-		return nil, fmt.Errorf("asset not found: %w", err)
-	}
-
-	// 验证是否为视频素材
-	if asset.Type != models.AssetTypeVideo {
-		return nil, fmt.Errorf("asset is not a video")
-	}
-
-	// 默认值
-	position := req.Position
-	if position == "" {
-		position = "last"
-	}
-	frameType := req.FrameType
-	if frameType == "" {
-		frameType = "first" // 提取的尾帧用作下一个分镜的首帧
-	}
-
-	// 生成唯一文件名
-	timestamp := time.Now().Format("20060102_150405")
-	fileName := fmt.Sprintf("frame_%s_%d_%s.jpg", position, assetID, timestamp)
-
-	// 创建临时目录
-	tmpDir := "./data/tmp"
-	if err := os.MkdirAll(tmpDir, 0755); err != nil {
-		return nil, fmt.Errorf("failed to create temp directory: %w", err)
-	}
-	outputPath := filepath.Join(tmpDir, fileName)
-
-	// 使用 FFmpeg 提取帧
-	_, err := s.ffmpeg.ExtractFrame(asset.URL, outputPath, position)
-	if err != nil {
-		return nil, fmt.Errorf("failed to extract frame: %w", err)
-	}
-
-	var imageURL string
-
-	// 根据存储类型上传
-	if s.ossStorage != nil {
-		// 上传到 OSS
-		url, err := s.ossStorage.UploadWithFilename(outputPath, "extracted_frames", fileName)
-		if err != nil {
-			s.log.Errorw("Failed to upload to OSS, falling back to local", "error", err)
-		} else {
-			imageURL = url
-			s.log.Infow("Frame uploaded to OSS", "url", url)
-			// 删除临时文件
-			os.Remove(outputPath)
-		}
-	}
-
-	// 如果 OSS 上传失败或未配置，使用本地存储
-	if imageURL == "" {
-		localPath := "./data/storage"
-		baseURL := "/static"
-		if s.cfg != nil && s.cfg.Storage.LocalPath != "" {
-			localPath = s.cfg.Storage.LocalPath
-		}
-		if s.cfg != nil && s.cfg.Storage.BaseURL != "" {
-			baseURL = s.cfg.Storage.BaseURL
-		}
-
-		// 移动文件到最终位置
-		finalDir := filepath.Join(localPath, "extracted_frames")
-		if err := os.MkdirAll(finalDir, 0755); err != nil {
-			return nil, fmt.Errorf("failed to create output directory: %w", err)
-		}
-		finalPath := filepath.Join(finalDir, fileName)
-		if err := os.Rename(outputPath, finalPath); err != nil {
-			return nil, fmt.Errorf("failed to move file: %w", err)
-		}
-
-		imageURL = fmt.Sprintf("%s/extracted_frames/%s", baseURL, fileName)
-	}
-
-	// 获取 DramaID
-	var dramaID uint
-	if asset.DramaID != nil {
-		dramaID = *asset.DramaID
-	}
-
-	// 创建 image_generation 记录
-	imageGen := &models.ImageGeneration{
-		DramaID:      dramaID,
-		StoryboardID: &req.StoryboardID,
-		Prompt:       fmt.Sprintf("Extracted %s frame from video asset #%d", position, assetID),
-		Status:       models.ImageStatusCompleted,
-		ImageURL:     &imageURL,
-		FrameType:    &frameType,
-	}
-
-	if err := s.db.Create(imageGen).Error; err != nil {
-		return nil, fmt.Errorf("failed to create image generation record: %w", err)
-	}
-
-	s.log.Infow("Frame extracted and saved",
-		"asset_id", assetID,
-		"position", position,
-		"image_gen_id", imageGen.ID,
-		"frame_type", frameType,
-		"image_url", imageURL)
-
-	return imageGen, nil
-}