Invocation import needs file upload option

That's loading everything into memory, in the client and once more on the backend, and then another time passing it into the celery task 😨. I think we need to fix the Galaxy API first before we can proceed here.

_Originally posted by @mvdbeek in https://github.com/galaxyproject/bioblend/pull/504#discussion_r2077075100_

Start by tracing invocation import through the Galaxy API and the Celery task, focusing on where uploaded files are currently loaded into memory. Review the related bioblend discussion and define the API and client entry points needed for a file-upload path; done means the invocation can use uploaded input without repeated in-memory copies.

Written by the indexing model from the issue text.