Resolve the rollback-compensation signing-window defect

Resolve the documented rbvl3 rollback-compensation defect in TaskVM, which is blocked by a race condition between the signing window and the confirmation gesture.

Background

TaskVM treats rollback as a central governance capability, distinguishing reversible, compensatable, and irreversible actions. In the development-era stress tier, rollback-compensation was the sole documented failure: the system could not reliably complete the compensation sequence when a signing-window race interfered with the confirmation gesture.

The problem is explicitly unresolved and technically concrete. Resolving it would improve the reliability of TaskVM’s recovery semantics, particularly for compensatable actions whose effects cannot be restored atomically but must instead be counteracted through follow-up GUI operations.