Checkpoint & rollback upgrades:
1. Enabled by default — checkpoints are now on for all new sessions.
Zero cost when no file-mutating tools fire. Disable with
checkpoints.enabled: false in config.yaml.
2. Diff preview — /rollback diff <N> shows a git diff between the
checkpoint and current working tree before committing to a restore.
3. File-level restore — /rollback <N> <file> restores a single file
from a checkpoint instead of the entire directory.
4. Conversation undo on rollback — when restoring files, the last
chat turn is automatically undone so the agent's context matches
the restored filesystem state.
5. Terminal command checkpoints — destructive terminal commands (rm,
mv, sed -i, truncate, git reset/clean, output redirects) now
trigger automatic checkpoints before execution. Previously only
write_file and patch were covered.
6. Change summary in listing — /rollback now shows file count and
+insertions/-deletions for each checkpoint.
7. Fixed dead code — removed duplicate _run_git call in
list_checkpoints with nonsensical --all if False condition.
8. Updated help text — /rollback with no args now shows available
subcommands (diff, file-level restore).
9e845a6e53