David debugged: Traced canvas external-link gap causing empty Spanish lecture notes

David refused to accept a surface-level explanation for missing slide content.

further, for his spanish class, he clicked on one of the lecture notes generations and went into the workspace, and none of the documents had any of the lecture slides inserted. they were just summaries. what is going on? dont we force all the pages of the lecture slides to be inserted??

The investigation found all 24 module topics for the Spanish course were Canvas page items whose HTML was a Google Slides link with shared_file_id = null. The lecture pipeline had treated them as page-backed runs, banned insert_pdf_pages, and had no file bytes to insert. David then asked why the pipeline hadn't downloaded the Google Slides, driving the eventual decision to design an upload-request modal for external file sources.