## Why
Reasoning summaries and nonzero command exits split adjacent exploration into separate groups, while compact history omitted exit codes. Replayed commands also failed to retain the same grouping as live commands.
## What changed
- Keep adjacent read, list, and search commands grouped across reasoning summaries and nonzero exits in both live and replayed history.
- Preserve reasoning in chronological order in the expanded transcript while omitting it from compact and raw history.
- Show nonzero exit codes in compact exploration entries and keep unsuccessful reads separate from successful read summaries. Render search exit code `1` without red failure styling, and label compound-command outcomes as `command exit`.
## Testing
Add regression coverage for live/replay rendering parity, reasoning order, grouping boundaries, and nonzero exit labels and colors. Update the overlapping-command test to verify that exploration stays grouped after a failure.
GitOrigin-RevId: 19c6ffec44c62c185fc6f79282c38e66468f7b80
71406edbd5