fix: resolve download failures and duplicate messages, add fast playlist detection

- Remove --audio-multi-streams flag (not supported by Alpine yt-dlp 2026.03.17)
- Reuse the fetching message as the format selection message to avoid duplicate text
- Add DetectPlaylist method for fast flat playlist detection before expensive GetMediaInfo
- This avoids stalls on YouTube Music radio URLs with large playlists

internal/handler/download.go

@@ -82,6 +82,14 @@ func (h *Handler) handleURLInput(ctx context.Context, chatID int64, text string,
 		fetchingMsgID = fetchingMsg.ID
 	}
 
+	// Fast playlist detection first — avoids expensive full metadata fetch for large playlists.
+	isPlaylist, plInfo, detectErr := h.YtDlp.DetectPlaylist(url)
+	if detectErr == nil && isPlaylist {
+		h.editText(ctx, chatID, fetchingMsgID, fmt.Sprintf("Playlist detected: %s (%d videos)", plInfo.Title, plInfo.PlaylistCount), nil)
+		h.handlePlaylist(ctx, chatID, userID, url, plInfo)
+		return
+	}
+
 	info, err := h.YtDlp.GetMediaInfo(url)
 	if err != nil {
 		errMsg := err.Error()
@@ -121,12 +129,6 @@ func (h *Handler) handleURLInput(ctx context.Context, chatID int64, text string,
 		}
 	}
 
-	if info.IsPlaylist {
-		h.editText(ctx, chatID, fetchingMsgID, fmt.Sprintf("Playlist detected: %s (%d videos)", info.Title, info.PlaylistCount), nil)
-		h.handlePlaylist(ctx, chatID, userID, url, info)
-		return
-	}
-
 	if len(info.Formats) == 0 {
 		h.editText(ctx, chatID, fetchingMsgID, "No formats available for this URL.", nil)
 		return
@@ -146,16 +148,6 @@ func (h *Handler) handleURLInput(ctx context.Context, chatID int64, text string,
 		}
 	}
 
-	// Edit the fetching message to show the media title, then send a separate photo preview.
-	previewText := fmt.Sprintf("Title: %s", info.Title)
-	if info.Uploader != "" {
-		previewText += fmt.Sprintf("\nChannel: %s", info.Uploader)
-	}
-	if info.Duration > 0 {
-		previewText += fmt.Sprintf("\nDuration: %s", formatDuration(info.Duration))
-	}
-	h.editText(ctx, chatID, fetchingMsgID, previewText, nil)
-
 	h.sendMediaPreview(ctx, chatID, info)
 
 	ss := &stepState{
@@ -181,7 +173,7 @@ func (h *Handler) handleURLInput(ctx context.Context, chatID int64, text string,
 		}
 	}
 	kb := formatKeyboard("format_", labels, ss.FormatIDs)
-	h.sendWithKB(ctx, chatID, "Select format:", kb)
+	h.editText(ctx, chatID, fetchingMsgID, "Select format:", &kb)
 }
 
 // handleFormatSelection processes a format pick from the unified list.