Session::execute runs each command inside catch_unwind: a panic that escapes
(any edit, import or export, from the UI, CLI, MCP or control channel)
becomes EngineError::Internal, the document and selection are restored to
before the command, and crash recovery is saved when enabled. The first
Session installs a panic hook that logs the message and location.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
