TUI: preserve detail pane scroll position (WL-0MN8QL3AO0008ZW3)

[SorraTheOrc]

Summary: Prevent the description panel from resetting its scroll position when the same item is re-rendered.

Changes:

• Only reset detail scroll when navigating to a different work item ID.

How to test (manual):

1. Start TUI, perform a search returning items with long descriptions.
2. Select an item, scroll down the description, trigger some UI update that re-renders details (e.g., focus changes, refresh).
3. Confirm the detail pane does not snap back to top.

Work item: WL-0MN8QL3AO0008ZW3

[SorraTheOrc]

This PR is not ready to merge yet because automated checks were not cleanly established in the review container, so regression safety is not fully demonstrated.

• Tests: container run was initially blocked before execution due missing test dependencies.
• Audit: implementation appears aligned with the acceptance criteria for preserving detail-pane scroll on same-item re-render; manual QA confirmation is still required.
• Code review: no blocker specific to this one-file PR diff was found.

Blocking issues

• Please provide a clean, reproducible test run from the intended review environment.
• Please confirm manual QA reproduction steps for the scroll-preservation behavior.

Non-blocking follow-up

• WL-0MN9F9UOO00258C4: add regression test for detail scroll preservation.
• WL-0MN9FA47D008KLNG: investigate spawnImpl consistency in TUI controller.