Disconnect a form from its template

Every submission generates a document from this template. This is the join between the two products. `field_map` is keyed by the **template's** variable (`headline.text` for canvas, `data.customer` for Typst). Each value is either a form field key written as a plain string, or an object for sources that are not a form answer: ```json { "template_id": "cm4tpl…", "field_map": { "headline.text": "video_title", "backdrop.src": "cover_image", "footer.text": { "kind": "fixed", "value": "© Acme" }, "issued.text": { "kind": "system", "value": "submitted_at" } }, "output_formats": ["png"], "public_links": true } ``` Nothing is matched by label or position — both sides are keys you chose. An `image` question maps onto an image variable: the uploaded file is what reaches the renderer. Generation runs in the background after a submission is accepted. Poll `GET /api/v1/forms/{id}/submissions`, whose `document` field carries the status and URL, or subscribe to `render.completed`.