Add clip extension from the last frame with FFmpeg stitching.

Let a finished player continue into a new MiniMax segment, then losslessly concat the parts and discard the intermediate files so the library keeps one extended MP4.

Co-authored-by: Cursor <cursoragent@cursor.com>

server/api/generate.post.ts

@@ -273,7 +273,9 @@ async function runGeneration(
       seed: job.library.seed,
       startedAt: job.startedAt,
       imageName: job.library.imageName,
-      imageSubfolder: job.library.imageSubfolder
+      imageSubfolder: job.library.imageSubfolder,
+      extendTmpDir: job.library.extendTmpDir,
+      extendPart1Path: job.library.extendPart1Path
     })
   }
   emitJob(job, { type: 'status', message: 'Job queued on ComfyUI', progress: 8 })