添加视频帧提取功能和阿里云OSS存储支持

- 新增从视频素材提取首帧/尾帧的功能，支持画面连续性编辑
- 添加阿里云OSS存储支持，可配置本地或OSS存储方式
- 导入视频素材时自动探测并更新视频时长信息
- 前端添加从素材提取尾帧的UI界面
- 添加FramePrompt模型的数据库迁移

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

infrastructure/storage/oss_storage.go

@@ -0,0 +1,122 @@
+package storage
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/aliyun/aliyun-oss-go-sdk/oss"
+	"github.com/drama-generator/backend/pkg/config"
+)
+
+// OssStorage 阿里云 OSS 存储实现
+type OssStorage struct {
+	client       *oss.Client
+	bucket       *oss.Bucket
+	bucketName   string
+	customDomain string
+	endpoint     string
+}
+
+// NewOssStorage 创建 OSS 存储实例
+func NewOssStorage(cfg *config.OssConfig) (*OssStorage, error) {
+	if cfg.Endpoint == "" || cfg.AccessKeyID == "" || cfg.AccessKeySecret == "" || cfg.BucketName == "" {
+		return nil, fmt.Errorf("OSS configuration is incomplete")
+	}
+
+	client, err := oss.New(cfg.Endpoint, cfg.AccessKeyID, cfg.AccessKeySecret)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create OSS client: %w", err)
+	}
+
+	bucket, err := client.Bucket(cfg.BucketName)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get OSS bucket: %w", err)
+	}
+
+	return &OssStorage{
+		client:       client,
+		bucket:       bucket,
+		bucketName:   cfg.BucketName,
+		customDomain: cfg.CustomDomain,
+		endpoint:     cfg.Endpoint,
+	}, nil
+}
+
+// Upload 上传文件到 OSS
+func (s *OssStorage) Upload(localPath, category string) (string, error) {
+	// 读取本地文件
+	file, err := os.Open(localPath)
+	if err != nil {
+		return "", fmt.Errorf("failed to open file: %w", err)
+	}
+	defer file.Close()
+
+	// 生成 OSS 对象键
+	ext := filepath.Ext(localPath)
+	timestamp := time.Now().Format("20060102_150405_000")
+	objectKey := fmt.Sprintf("%s/%s%s", category, timestamp, ext)
+
+	// 上传到 OSS
+	err = s.bucket.PutObject(objectKey, file)
+	if err != nil {
+		return "", fmt.Errorf("failed to upload to OSS: %w", err)
+	}
+
+	// 构建访问 URL
+	url := s.GetURL(objectKey)
+	return url, nil
+}
+
+// UploadWithFilename 使用指定文件名上传文件到 OSS
+func (s *OssStorage) UploadWithFilename(localPath, category, filename string) (string, error) {
+	file, err := os.Open(localPath)
+	if err != nil {
+		return "", fmt.Errorf("failed to open file: %w", err)
+	}
+	defer file.Close()
+
+	objectKey := fmt.Sprintf("%s/%s", category, filename)
+
+	err = s.bucket.PutObject(objectKey, file)
+	if err != nil {
+		return "", fmt.Errorf("failed to upload to OSS: %w", err)
+	}
+
+	return s.GetURL(objectKey), nil
+}
+
+// GetURL 获取 OSS 对象的访问 URL
+func (s *OssStorage) GetURL(objectKey string) string {
+	if s.customDomain != "" {
+		// 使用自定义域名（CDN）
+		domain := strings.TrimSuffix(s.customDomain, "/")
+		if !strings.HasPrefix(domain, "http") {
+			domain = "https://" + domain
+		}
+		return fmt.Sprintf("%s/%s", domain, objectKey)
+	}
+
+	// 使用默认 OSS 域名
+	return fmt.Sprintf("https://%s.%s/%s", s.bucketName, s.endpoint, objectKey)
+}
+
+// Delete 删除 OSS 对象
+func (s *OssStorage) Delete(objectKey string) error {
+	err := s.bucket.DeleteObject(objectKey)
+	if err != nil {
+		return fmt.Errorf("failed to delete OSS object: %w", err)
+	}
+	return nil
+}
+
+// IsConfigured 检查 OSS 是否已配置
+func IsOssConfigured(cfg *config.OssConfig) bool {
+	return cfg != nil &&
+		cfg.Endpoint != "" &&
+		cfg.AccessKeyID != "" &&
+		cfg.AccessKeySecret != "" &&
+		cfg.BucketName != ""
+}