Ship duration control, hidden previews, job resume, and desktop file purge.

The slider never left this machine, so deploy the generate UI with separate input/output hide toggles, reconnect in-progress jobs after refresh, and delete Comfy input/output files after they are saved to the library.

server/api/library/stills.post.ts

@@ -23,7 +23,7 @@ export default defineEventHandler(async (event) => {
   if (!folderId) {
     throw createError({ statusCode: 400, statusMessage: 'Create a library folder first' })
   }
-  assertFolderAccess(event, folderId)
+  assertFolderExists(event, folderId)
   const still = await saveStill({
     ownerKey: owner,
     folderId,