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/api/library/stills/[id]/backup.post.ts

@@ -0,0 +1,38 @@
+import { readFileSync } from 'node:fs'
+import { isXaigenStudio } from '~/utils/videoModels'
+import { assertLibraryOwner, getStill, stillPath } from '~/server/utils/library'
+
+export default defineEventHandler(async (event) => {
+  if (isXaigenStudio()) {
+    throw createError({ statusCode: 404, statusMessage: 'Not found' })
+  }
+  const config = useRuntimeConfig()
+  const url = String(config.backupStudioUrl || process.env.BACKUP_STUDIO_URL || '').replace(/\/$/, '')
+  const token = String(config.backupStudioToken || process.env.BACKUP_STUDIO_TOKEN || '').trim()
+  if (!url || !token) {
+    throw createError({ statusCode: 503, statusMessage: 'Backup studio is not configured' })
+  }
+  const { owner } = assertLibraryOwner(event)
+  const id = String(getRouterParam(event, 'id') || '')
+  const still = getStill(owner, id)
+  const path = stillPath(owner, still.id)
+  const data = readFileSync(path)
+  const body = new FormData()
+  body.append('image', new Blob([Uint8Array.from(data)]), still.filename || 'still.png')
+  body.append('name', still.name || still.filename || 'still')
+  body.append('width', String(still.width || 0))
+  body.append('height', String(still.height || 0))
+  const res = await fetch(`${url}/api/library/backup-ingest`, {
+    method: 'POST',
+    headers: { Authorization: `Bearer ${token}` },
+    body
+  })
+  if (!res.ok) {
+    const message = await res.text().catch(() => '')
+    throw createError({
+      statusCode: res.status === 401 ? 502 : res.status,
+      statusMessage: message || 'Backup studio refused the still'
+    })
+  }
+  return { ok: true }
+})