[QA] ✅ VERIFICATION PASSED - All acceptance criteria met. Full test suite passes (656/656). Implementation correctly integrates SessionHistory with live updates, toggle/scroll, and balanced layout. See /tmp/qa-PLOW-28.md for detailed report.

## Implementation Complete ### Changes Made **SessionHistoryWidget enhancements** (src/trckr_plow/tui/widgets.py:508-733): - Added expanded/collapsed display modes with reactive property - Added scrollable ticket list showing issue_id, title, status, duration - Added scroll_up/scroll_down methods with scroll indicators - Added toggle_expanded method for switching modes - Added add_ticket_from_processed for integration with SessionHistory model - Added ticket_count property - Enhanced record_completion to accept full ticket details **PlowApp integration** (src/trckr_plow/tui/app.py:145-389): - Imported SessionHistory model - Added session_history parameter to __init__ - Added keybindings: h (toggle history), j/k (scroll down/up) - Added _on_state_change handling to detect ticket completions - Added _record_ticket_completion to sync with widget - Added _sync_session_history_to_widget for loading existing history - Added session_history property **External stylesheet** (src/trckr_plow/tui/plow.tcss): - Created optional external TCSS file for layout customization **Tests** (tests/test_tui.py:551-749): - Added 8 new tests for SessionHistoryWidget functionality ### Verification - All 656 tests pass - Linting passes with no errors - Coverage maintained at 69% ### Acceptance Criteria Met - Session history visible in TUI (in right pane) - Updates live as tickets complete (via _on_state_change callback) - Layout is balanced and usable (2fr:1fr split) - Can toggle/scroll history view (h, j, k keybindings) - Works with existing graph and log widgets