forked from 1b-agent/fieldcraft-upstream
geometry.open with "model": "new" cleared the model but kept the session's file path, so File > Save wrote the new model over the previous one. The path and the revision saved there (which document the session is) were not part of the undo state. A step now records the document when its command changed it: the new model is untitled and unsaved; undo restores the old file and its clean state, redo the untitled model (or the file it was saved to since). Co-Authored-By: Claude Opus 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_01UhhZMBTviDQxZvwnyP89fo