Record caller cancellation versus the owned deadline once and share that provenance through helper execution, scenario waits and finalization. Preserve independent failures and partial reports, consolidate scenario failure handling and dispose listeners on every exit.
Fixes#5056
Carry caller and runtime deadline cancellation through helper cleanup, preserve command-owner reasons and physical failures, and retain collected scenario reports with typed terminal errors.
BREAKING CHANGE: failed or cancelled native UI scenarios now return typed errors with the collected report in partial_observation instead of successful reports containing failed or cancelled steps.
Refs #4227
morluto