Upload multiple PDF files from ChatGPT file attachments (download URLs).
Use this when the user provides multiple file attachments in ChatGPT.
Downloads each PDF from its signed URL and stores it.
Returns session_id and a list of job_ids.
MANDATORY WORKFLOW before calling this tool:
1. ALWAYS call check_upload_status FIRST — even if you think the files are new.
2. Only include files confirmed absent from check_upload_status. If ALL files are already
uploaded, skip batch_upload_pdf entirely and reuse the existing job_ids.
3. Reuse job_ids from already_uploaded — do NOT re-upload those files.
Skipping step 1 and calling batch_upload_pdf directly is FORBIDDEN.
After batch_upload_pdf completes: if the user requested a comparison, call
'compare_pdfs' with the returned job_ids immediately.
Connector