Specification: Preserve an open task board during updates

Branch: t3/board-live-refresh | Created: 2026-10-08 Input: Continue native UI/UX quality; publish and merge all focused PRs.

User story1 (P1)

While inspecting a scrolled board, background task events update its data without closing/reopening it or losing the user's place. Acceptance: Same dialog and same task row survive metadata changes. Horizontal and vertical position remain; insertion/removal above a scrolled viewport preserves its surviving top card. At the top, new tasks remain visible. Moving a focused task follows its identity to its new column and reveals it; unrelated movement does not recenter. Removed focused task uses adjacent surviving row or native dialog focus. Closing before async refresh completes leaves it closed.

Requirements

Key rows by task ID, use current pane destination on activation, update counts and conditional Done subset notice. Empty/nonempty transitions keep dialog identity. No new IPC/storage/dependencies/motion; terminal widgets unchanged.

Success criteria

Production App regression first reproduces dialog replacement. Native tests then prove dialog/row identity, updates, focus, scroll anchors, movement/removal, pane target changes and empty transitions; existing navigation tests and full gate pass. Inspect light/dark renders before merge.

Clarifications

Grok scope review identified that revealing Needs you before fixing replacement would recenter on each event. Therefore this PR precedes initial-attention reveal. No architectural deviation; native widget reconciliation follows existing GUI direction.