Document the backtrack/rollback state machine and invariants between the
transcript overlay, in-flight “live tail”, and core thread state (tui + tui2).
Also adjust behavior for correctness:
- Track a single pending rollback and block additional rollbacks until core responds.
- Defer trimming transcript cells until ThreadRolledBack for the active session.
- Clear the guard on ThreadRollbackFailed so the user can retry.
- After a confirmed trim, schedule a one-shot scrollback refresh on the next draw.
- Clear stale pending rollback state when switching sessions.
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Co-authored-by: Josh McKinney <joshka@openai.com>
Ahmed Ibrahim
764f3c7d03