Session::execute ran a command under guard::run but normalised what it
changed afterwards, outside it: a panic in normalisation escaped execute
instead of becoming EngineError::Internal with the edit rolled back. Inside
a batch it unwound through Session::grouped, which then never restored the
undo limit it had lifted or ended the group. Normalising is now the last
step of the guarded result chain, so a panic there fails the command like
one in the command itself (and a batch step fails like any other failed
step); live text previews normalise under the guard too.
The other half of #1085, restoring grouped()'s state when its closure
panics, is left alone: #1419 rewrites that function.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LvG6E2qDnjtMzfPVuEP7iH
