Upload a PowerPoint or PDF and make a slideshow from it

Uploads a .pptx or .pdf file (multipart/form-data: a file part up to 100 MB, optional title field; the file name is used otherwise) and creates a slideshow from it, one slide per page, shown as it is. Returns the new slideshow (201) and queues its render: it plays once renderStatus is Completed, so poll GET /v1/slideshows/{id} at most every 5 seconds. To have AI Studio write new slides from a document instead, use POST /v1/slideshows/{id}/slides/ai with handler: document.