Uploads a utility bill document for a project and starts an asynchronous OCR parse of its contents. The file upload itself is handled synchronously inside this endpoint, so a user_file_id is returned immediately along with the job_id for the parse step.

The bill bytes are sent as a raw request body (not multipart/JSON), with the original filename carried in the Content-Disposition header. Accepted formats: PDF, JPG, JPEG, PNG, GIF, WEBP.

Last-parse-wins semantics. Each completed parse replaces the consumption data derived from any previously parsed bill on the same project — only the most recently parsed bill feeds the project's load profile. Because parse jobs run asynchronously and are not strictly FIFO, an earlier upload that finishes parsing after a later upload will become the active bill. Older bill files persist in storage but no longer contribute to the project's consumption values. This matches the behavior of the in-app utility bill upload UI.

Note that this is an asynchronous endpoint. See the Asynchronous Endpoints appendix for more info.