Create Document Upload
Return a presigned URL for a single document.
Unlike the tabular /uploads endpoint this writes no DB row — the
document only becomes relevant when its upload_key is referenced
by a subsequent induce_schema or tabularize call.
Caller-supplied document_id becomes part of the S3 key
(users/{user_id}/documents/{document_id}/raw.{ext}); collisions
overwrite, which is fine for the SDK’s intended workflow but is
something callers should be aware of.
Body
POST /v1/uploads/documents -- request a presigned URL for one file.
Response
Successful Response
Reference to use as DocumentRef.upload_key in induce/tabularize.
application/pdf, image/png, image/jpeg, image/gif, image/webp, text/plain Seconds until the upload URL expires.