- Tracked the previous live child in TranscriptContainer and forced a one-off recompute when a block leaves live status.
- Skipped snapshot reuse for that transitioning block so coalesced finalize-and-append frames seal transcript blocks at their final content.
- Added a regression test covering the stale-prefix freeze case on ED3-risk terminals and confirming the frozen block stays unchanged until thaw.
- Added assistant-message completion state and stable-line count reporting.
- Added transcript stable-row aggregation and snapshot replay to keep unstable rows out of scrollback.
- Added TUI stable scrollback boundary APIs and stable-prefix commit path.
- Added regression tests proving unstable rows stay out of scrollback until stabilized.
- Added TranscriptContainer that snapshots non-live blocks to avoid stale scrollback duplicates.
- Thawed snapshots at prompt-submit checkpoints for reconciliation.
- Repainted eager streaming tail on overflowing shrink to unfreeze UI (issue #1682).
can1357