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>
Closes#13
## Summary
- add Python sandbox execution APIs for command and callable workflows
- consolidate sandbox policy fixtures and expand e2e test coverage for policy and Python exec paths
- update CI/build config and images for sandbox e2e execution dependencies
## Test Plan
- mise run pre-commit
Drew Newberry