fix: add --progress flag to force progress in non-TTY pipes

yt-dlp suppresses progress output by default when not in a TTY.
The --progress flag overrides this. Without it, readProgress sees
only 4 stderr lines (no [download] progress) and reports 0 matches.
This was the root cause of progress always showing 0.0%.

internal/dl/ytdlp.go

@@ -283,8 +283,9 @@ func (c *Client) StartDownload(job *domain.DownloadJob, downloadDir string) (<-c
 	outputPath := filepath.Join(downloadDir, job.ID+"_%(id)s.%(ext)s")
 	args = append(args, "--output", outputPath)
 
-	// Use --newline so each progress line is newline-delimited in pipe
-	args = append(args, "--newline")
+	// --progress forces progress output in non-TTY (pipe) environments
+	// --newline uses \n instead of \r so bufio.Scanner can read line-by-line
+	args = append(args, "--progress", "--newline")
 
 	// Language selection if specified
 	if job.Language != "" {