Split prompts into pre/prompt/post and tidy the AIGen video form.

Keep wrappers off the library mid-prompt so Use as input and Extend restore the same split, send stills to xAIGen as hidden inputs, and stop the two-column library from growing with the list.

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

server/utils/imageChain.ts

@@ -8,6 +8,7 @@ import { imageDimensions } from '~/server/utils/resolution'
 import { emitChainJob } from '~/server/utils/watch'
 import { saveStill, stillChainName } from '~/server/utils/library'
 import { comfyJobPrefix } from '~/utils/outputNames'
+import { composePromptParts } from '~/utils/promptParts'
 
 export type EditImageFile = { filename: string; data: Buffer; type?: string }
 
@@ -66,7 +67,8 @@ export async function runEdit(job: Job, params: EditRunParams) {
       for (let index = 0; index < prompts.length; index++) {
         if (job.status === 'cancelled') throw new Error('Job interrupted.')
         if (index > 0 && library.stopAfterCurrent === true) break
-        const prompt = (batch || index === 0) ? composeFillPrompt(prompts[index], filled.padded) : prompts[index]
+        const mid = (batch || index === 0) ? composeFillPrompt(prompts[index], filled.padded) : prompts[index]
+        const prompt = composePromptParts(library.promptPre || '', mid, library.promptPost || '')
         const last = index === prompts.length - 1
         if (index > 0) {
           await ensureComfyReady((status) => {
@@ -79,7 +81,7 @@ export async function runEdit(job: Job, params: EditRunParams) {
           }, { skipBusyWait: true })
         }
         const seed = index === 0 ? params.seed : Math.floor(Math.random() * 2_147_483_647)
-        library.prompt = prompt
+        library.prompt = mid
         library.seed = seed
         library.chainIndex = index
         library.chainStep = index + 1
@@ -164,7 +166,9 @@ export async function runEdit(job: Job, params: EditRunParams) {
           hideInput: job.hideThumbnail === true,
           role: 'output',
           name: passName || undefined,
-          prompt,
+          prompt: mid,
+          promptPre: library.promptPre,
+          promptPost: library.promptPost,
           familyId: library.familyId,
           parentStillId: batch ? library.stillId : parentStillId,
           chainIndex: index,