Add video download failure reporting feature

- Introduced a new API endpoint `POST /api/v1/video/remove_watermark/report_failure` for reporting download failures.
- Added a new database table `video_download_failures` to store details about failed downloads, including domain, URL, error message, and reporting metadata.
- Updated the video handler to process failure reports and save them to the database.
- Enhanced documentation to include details about the new reporting feature and its usage.

internal/remove_watermark/service/video_service.go

@@ -19,7 +19,7 @@ import (
 	rmmodel "wx_service/internal/remove_watermark/model"
 )
 
-const removeWatermarkEndpoint = "https://api.23bt.cn/api/d1w/index"
+const removeWatermarkEndpoint = "https://api.23bt.cn/api/dsp/index"
 
 var (
 	// 从用户输入的文本里“抓取 URL”的简单正则（找到第一个 http/https 链接）
@@ -56,6 +56,15 @@ func (e *ThirdPartyError) Error() string {
 	return fmt.Sprintf("third-party api error: status=%d message=%s", e.StatusCode, e.Message)
 }
 
+type DownloadFailureReport struct {
+	Domain       string
+	FailedURL    string
+	ErrorMessage string
+	ReportedAt   time.Time
+	UserAgent    string
+	ClientIP     string
+}
+
 func NewVideoService(db *gorm.DB, cfg config.ShortVideoConfig) (*VideoService, error) {
 	timeout := cfg.RequestTimeout
 	if timeout <= 0 {
@@ -253,3 +262,33 @@ func truncateString(input string, max int) string {
 	}
 	return input[:max]
 }
+
+func (s *VideoService) ReportDownloadFailure(ctx context.Context, report DownloadFailureReport) error {
+	if report.ReportedAt.IsZero() {
+		report.ReportedAt = time.Now()
+	}
+
+	if report.Domain == "" && report.FailedURL != "" {
+		if parsed, err := url.Parse(report.FailedURL); err == nil {
+			report.Domain = parsed.Host
+		}
+	}
+
+	entry := rmmodel.VideoDownloadFailure{
+		Domain:       report.Domain,
+		FailedURL:    report.FailedURL,
+		ErrorMessage: truncateString(report.ErrorMessage, 2000),
+		ReportedAt:   report.ReportedAt,
+		UserAgent:    truncateString(report.UserAgent, 255),
+		ClientIP:     truncateString(report.ClientIP, 64),
+	}
+
+	if entry.FailedURL == "" {
+		return errors.New("failed_url is required")
+	}
+
+	if err := s.db.WithContext(ctx).Create(&entry).Error; err != nil {
+		return fmt.Errorf("save download failure report: %w", err)
+	}
+	return nil
+}