* feat(sandbox): add gpu sandbox scheduling support
Allow sandbox creation to request GPU resources explicitly or infer them from GPU image names. This wires GPU intent through bootstrap, validates gateway support, and adds dedicated GPU E2E coverage for follow-up cluster testing.
Closes#101
Add pytest-xdist for parallel e2e test execution with configurable
concurrency. Default to 5 workers; override via E2E_PARALLEL env var
(accepts a number or 'auto' for CPU-count matching). Make session-scoped
mock inference route fixtures worker-safe by incorporating the xdist
worker_id into route names and routing hints.
Co-authored-by: John Myers <johntmyers@users.noreply.github.com>
Piotr Mlocek