edit.undo cancelled an open interaction (rolling back the typing session
or drag preview without recording it) and then undid the step before it:
one Undo removed two steps, and the typing could not be redone. Undo now
commits the interaction first, so it is the step taken back and Redo can
restore it; commit_interaction does nothing when nothing is open or
nothing changed.
Fixes#159
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01U9TrG4w49oSRYbP3cqxA3D