Each browser gets a UUID stored in localStorage, set as a cookie,
and attached to every API call. Files go to session-specific dirs:
/mnt/converter/in/{guid}/ — uploads, downloads, SCP pulls
/mnt/converter/out/{guid}/ — converted QCOW2s
Changes:
- base.html: generates UUID via crypto.randomUUID(), stores in
localStorage + cookie, exposes as window.VM_BENCH_SID
- Frontend: all endpoints accept session_id, _staging() helper
creates session-aware paths on demand
- JavaScript: session_id appended to all FormData, set as
X-Session-ID header on raw uploads
- Backend models: JobSubmissionRequest.session_id field added
- Provisioner: _staging_in/_staging_out helpers, source path
resolution uses session-aware directory
- Converter: extract_if_needed skips re-extraction if dir exists