Join pre/prompt/post into the first MiniMax prompt, not only later shots.

The motion prompt field is what Comfy actually runs. Wrappers are now composed into that string on submit, and shot 1 falls back to it if the separate pre/post fields do not arrive.

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

server/api/v2/generate.post.ts

@@ -27,6 +27,7 @@ import {
   type ImageV2Task
 } from '~/utils/imageV2'
 import { isXaigenStudio } from '~/utils/videoModels'
+import { ingestPromptParts } from '~/utils/promptParts'
 import { listStudioLoras, parsePostedLoraStack, persistLoraFields, assertImageV2LoraStack } from '~/server/utils/loras'
 import { getStill, rememberInputStill, stillPath } from '~/server/utils/library'
 import { existsSync, readFileSync } from 'node:fs'
@@ -136,10 +137,11 @@ export default defineEventHandler(async (event) => {
     fields.task,
     mode === 'generate' ? 't2i' : mode === 'refine' ? 'refine' : 'scene'
   )
-  const promptMid = String(fields.prompt || '').trim()
-  const promptPre = String(fields.promptPre || '').trim()
-  const promptPost = String(fields.promptPost || '').trim()
-  const prompt = promptMid
+  const posted = ingestPromptParts(fields)
+  const promptMid = posted.promptMid
+  const promptPre = posted.promptPre
+  const promptPost = posted.promptPost
+  const prompt = posted.prompt
   const extraPasses = parsePasses(fields.passes)
   const passMode = parseImagePassMode(fields.passMode)
   const aspect = parseImageAspect(fields.aspect)