- New /session/configure/{analysis_id} page with VM config + disk table
- Each disk has radio (boot selection) + shrink checkbox + size input
- Per-disk shrink control — check to enable, set custom size
- Disks sorted smallest first, boot disk pre-selected as largest
- Submit via /session/configure/submit, then /session/status/{job_id} polling
- Landpage download/SCP flow redirects to configure after analysis completes
