渐进式生成播放：fMP4 前 4 个分片就绪即返回播放列表开始起播，后台边转边补 ENDLIST，消除整集封装等待的黑屏缓冲

internal/app/emby_playback.go

@@ -190,7 +190,7 @@ func (app *UIApp) prepareEmbyPlayback(parent context.Context, session *playbackS
 			} else if session.embyProcessing == "audio" {
 				mode = "audio"
 			}
-			err = app.planMedia(ctx, media, playbackClientCapabilities{MP4: true, NativeHLS: true}, mode, sourceFromDramaID(task.DramaID), origin, base, query)
+			err = app.planMedia(ctx, media, playbackClientCapabilities{MP4: true, NativeHLS: true}, mode, sourceFromDramaID(task.DramaID), origin, base, query, 0)
 			if err == nil {
 				duration = media.plan.Duration
 				if media.plan.Player == "legacy" {