BUG - AI stalls if a counterspell is shown and rolled back.

Play against AI.
Have AI get a target lock on you.
Play any card.
Have AI counter it.
Roll back to the start of the turn.
All AI will now completely forgo all gamestate actions, casting of spells, assigning blockers, or anything that would advance the board state until the angry AI has countered your spell. It doesn't matter what it is. It will counter it.
The angry AI will attack as normal, but if unable to swing at you safely, it will kill the other two AI players, as they will not block.
All AI will discard to handsize due to not playing any spells, or lands.
Once the counterspell has been used, AI will begin functioning as normal.

No file, test, or entry point is named. Start by reproducing the listed AI-versus-AI rollback sequence, then trace the rollback and counterspell handling paths. Done means the AI resumes normal game-state actions after the rollback and counterspell instead of stalling.

Written by the indexing model from the issue text.