Group extension chains in the library and add shot-script queues.

Keep every saved segment, show the longest clip with an expand list, branch on extend, and parse shot 2/3 blocks into a shared-duration queue with live part status.

server/utils/pending.ts

@@ -22,6 +22,9 @@ export interface PendingJob {
   imageSubfolder?: string
   extendTmpDir?: string
   extendPart1Path?: string
+  familyId?: string
+  parentClipId?: string
+  chainIndex?: number
 }
 
 function pendingRoot() {
@@ -102,7 +105,10 @@ export async function completePendingIfReady(pending: PendingJob) {
     hideThumbnail: pending.hideThumbnail,
     video: buffer,
     thumb: null,
-    comfyFilename: video.filename
+    comfyFilename: video.filename,
+    familyId: pending.familyId,
+    parentClipId: pending.parentClipId,
+    chainIndex: pending.chainIndex
   })
   await purgeComfyArtifacts({ video, imageName: pending.imageName, imageSubfolder: pending.imageSubfolder, promptId: pending.promptId })
   deletePendingJob(pending.jobId)