David decided: Parallelised prefetch without requiring extension upgrade

After confirming prefetch was serial, David approved concurrency increases but drew a hard line on the extension.

wait it requires an extension upgrade? i dont wanna do that. what numbers do we use that dont require this

The final parameters were PREFETCH_ITEM_CONCURRENCY=6 and dispatcher lanes raised from 8 to 12. David also asked the agent to explain the PREFETCH_LIBREOFFICE_CONCURRENCY parameter — a container-level memory guard rather than a per-user limit — and accepted the explanation that it protects against RAM fan-out during parallel PPTX-to-PDF conversions.