- abort locked engine downloads and extraction on process interruption
- recover only dead-PID staging trees while preserving active and legacy trees
- normalize Ubuntu mirrors and bound apt in release jobs
- cover cancellation, orphan cleanup, and workflow contracts with focused tests
- refresh compatible npm and Cargo lockfile dependencies
- update locked Windows and Linux FFmpeg provider artifacts by checksum
- publish verified engine payloads with interrupted-promotion recovery
- retry Windows-safe cleanup and cover worst-case promotion states