4a20b51ca8
- Added auto-sealing logic to `FinalizableBlock` to finalize displaceable snapshots when they enter the scrollback area. - Updated TUI frame emission to publish committed rows and clamp them to segment bounds, ensuring accurate component updates. - Introduced component tracking and cleanup in event controller tests to prevent resource leaks during finalization. - Validated state transitions and post-emit synchronization through comprehensive new test suites for transcript and TUI components.